ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Coherent raman spectroscopy of nitrogen molecules and clusters in supersonic jets (1991)
    Springer
    Applied physics 52 (1991), S. 84-89 
    Details
    ISSN: 1432-0649
    Keywords: 36.40 ; 42.65 ; 47.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Coherent Stokes and anti-Stokes Raman scattering CSRS and CARS have been employed to study the spectroscopy of nitrogen molecules and clusters in the expansion of a supersonic jet. In the vibrational spectrum, at strong stagnation conditions, an intense redshifted peak is observed which can be assigned to the intramolecular vibrations in large N2 clusters having adopted the β-phase structure. Another weak feature is assigned to nitrogen clusters in the α-phase. In the rotational region of the spectrum only monomer features have been observed. The failing to observe librational motions is consistent with the finding that the nitrogen clusters are predominantly in the orientationally unordered β-phase. The low rotational temperature suggests supercooling of the β-phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00357660
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Surface spectroscopy (1982)
    Springer
    Applied physics 28 (1982), S. 229-232 
    Details
    ISSN: 1432-0649
    Keywords: 82.65 ; 68 ; 36.40 ; 78 ; 42.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697849
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Experimental study of enhanced emission of the laser-ablated plume in backing gas (1994)
    Springer
    Applied physics 58 (1994), S. 143-148 
    Details
    ISSN: 1432-0649
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The effects of background gases on the optical emission of the excimer-laser-ablated plume from a brass target have been studied experimentally. It is found that the plume emission can be enhanced significantly in a proper gas ambient. In hydrogen, the highest peak intensity is detected, and in argon, there is a distinctive difference in the pressure-dependent emission between in He and in the other three gases, Ar, N2 and H2. Moreover, the monitored line peak intensity remains unchanged in Ar and N2 and increases in H2 within a distance above the target surface; but in He, the observed peak intensity decreases with distance like in vacuum. Furthermore, the emissions of several more atomic lines of Cu and Zn atoms from the plume are also found to be enhanced in the same manner in gas ambient. Some physical processes involved in the plume expansion and the possible mechanisms for the enhanced emission of the plume in backing gas are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01082349
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Laser-fluorescence diagnostics for condensation in laser-ablated copper plasmas (1991)
    Springer
    Applied physics 53 (1991), S. 353-361 
    Details
    ISSN: 1432-0649
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We are investigating the thermodynamic conditions under which condensation occurs in laser ablated copper plasma plumes. The plasma is created by XeCl excimer laser ablation (308 nm, 300 mJ/pulse) at power densities from 500–1000 MW/cm2 into backing pressures of helium in the range 0–50 torr. We use laser-induced fluorescence (LIF) to probe velocity and relative density of both atomic copper and the copper dimer molecule, Cu2, which is formed during condensation onset. At low pressure (10 mtorr), the atomic Cu velocity peaks at approximately 2×106 cm/s. Copper dimer time-of-flight data suggest that condensation onset occurs after the Cu atoms have slowed very significantly. Excitation scans of the Cu2A-X (0,0) and (1,1) bands yield a rotational and vibrational temperature in the neighborhood of 300 K for all conditions studied. Such low temperatures support the theory that Cu2 is formed under thermally and translationally cold conditions. Direct laser beam absorption is used to determine the number density of atomic copper. Typical densities attained with 5 torr of helium backing gas are 6–8×1013 cm−3. Rayleigh scattering from particulate is easily observable under conditions favorable to particulate production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331827
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Temperature measurements in CO2-laser-induced pyrolysis flames for SiC and ternary SiC/C/B powder synthesis by means of CARS (1996)
    Springer
    Applied physics 62 (1996), S. 609-612 
    Details
    ISSN: 1432-0649
    Keywords: 36.40 ; 42.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The hot luminescent reaction zones of CO2-laser-induced pyrolysis flames using SiH4/C2H2 gas mixtures with different silane to acetylene ratios and with and without diborane additives were investigated by means of H2 Q-branch CARS spectroscopy, leading to spatial temperature profiles in gas flow direction. In the case of B2H6 additive to the stoichiometric SiH4/C2H2 mixture a high temperature plateau (≈ 800–1000 K) of the reactant gas volume develops already several millimetres before reaching the CO2-laser focus line. This precursor preheating zone could be explained by the catalytic effect of boron atoms or boron-containing intermediate species in the flame. A similar behaviour for acetylene-rich flames operating at half laser power was not observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081699
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Cluster emission under ion bombardment of metallic targets (1991)
    Springer
    Applied physics 52 (1991), S. 213-217 
    Details
    ISSN: 1432-0630
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Mass spectroscopic studies of the neutral particles sputtered by Ar+ ions at 8 keV from polycrystaline samples have been performed, using non-resonant laser ionization and subsequent time-of-flight mass spectroscopy. Besides sputtered atoms, also dimer and trimer contributions in the order of 10−1 to 10−2 and 10−3 to 10−4, respectively, are found in the sputtered flux. The data obtained here together with previously published data by other groups for different bombarding energies provide strong support for the validity of the recombination model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324422
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Metal particles on surfaces-desorption, optical spectra, and laser-induced size manipulation (1990)
    Springer
    Applied physics 51 (1990), S. 271-280 
    Details
    ISSN: 1432-0630
    Keywords: 36.40 ; 79.20 ; 82.65 ; 68.45
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Desorption induced by electronic excitation with laser light is discussed. Emphasis is placed on nonthermal desorption where surface plasma excitation in small particles precedes the rupture of the surface chemical bond. A scenario for the mechanism underlying such a process is proposed. In this context, calculations of the electronic spectra of small sodium particles are presented and the influence of different multipole orders of the collective electron oscillation, of different shapes of the clusters and of the substrate are outlined. Furthermore, manipulation of the size distribution of metal particles on supports is described as an application of the effect. This allows the preparation of very special surfaces with novel physical and chemical properties. Methods to characterize such adsorbate-substrate combinations, especially by use of the optical spectra of the particles, are also discussed. Finally, prospects for future experiments in this field are outlined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Dynamics of C 60 + surface impact: Rolling, deformation, disintegration, and deposition on HOPG graphite (1992)
    Springer
    Applied physics 55 (1992), S. 461-467 
    Details
    ISSN: 1432-0630
    Keywords: 36.40 ; 61.80.L ; 79.20.N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Cluster surface collisions of C+ 60 (Buckminsterfullerene) ions with pyrolytic graphite are studied by time of flight mass spectroscopy in the energy range of 100 eV to 1500 eV at oblique angles of incidence extending our previous studies with steep angles of incidence. Analysis of the velocity dependence of the scattered cluster ions reveals that the normal and tangential component of the ion velocity have different significance for the collision dynamics. The tangential component is partially transformed into rotational energy of the C+ 60 during the interaction with the surface as may be explained by an intuitive and astonishingly simple rolling ball model. In contrast, the normal component of the velocity appears to determine the amount of energy transferred into vibrational and deformational energy of projectile and target. At high “normal energies” the C+ 60 disintegrate significantly and can also be partially deposited onto the surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00348333
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Optical second-harmonic generation by supported metal clusters: Size and shape effects (1995)
    Springer
    Applied physics 60 (1995), S. 607-612 
    Details
    ISSN: 1432-0630
    Keywords: 42.65 ; 68.55 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Optical Second Harmonic Generation (SHG) by metal clusters has been investigated. For this purpose clusters were generated by the deposition and nucleation of metal atoms on a LiF(100) single crystal surface under ultrahigh vacuum conditions. The size and shape of the metal particles was characterized by optical transmission spectroscopy. The SHG intensity was detected in situ as a function of cluster size during the nucleation. Fundamental wavelengths of λ=1064 and 532 nm were used and the SHG signal was measured for different polarization combinations of the incident and registered light. SH radiation is detectable for particles as small as approximately 1 nm. The signal grows monotonically as a function of particle size, passes a maximum and finally drops off. This behavior is discussed in terms of resonant enhancement of the signal by surface plasmon excitation and changes ofχ (2) as a function of particle size and shape. In further experiments the chemisorption of oxygen on the surface of the metal particles was studied. The SH signal decreases as a function of oxygen coverage and amounts to only about 15% of the initial value upon chemisorption of one monolayer. This indicates that the SH signal originates almost exclusively from the surface of the clean clusters and that higher order bulk contributions are negligible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01538536
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Non-thermal laser-induced desorption of metal atoms with bimodal kinetic energy distribution (1996)
    Springer
    Applied physics 63 (1996), S. 315-320 
    Details
    ISSN: 1432-0630
    Keywords: 61.80.Ba ; 68.55.Jk ; 79.20.Ds ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Laser-induced desorption of metal atoms at low rate has been studied for pulsed excitation with wavelengths of λ = 266, 355, 532 and 1064 nm. For this purpose sodium adsorbed on quartz served as a model system. The detached Na atoms were photo-ionized with the light of a second laser operating at λ = 193 nm and their kinetic energy distribution was determined by time-of-flight measurements. For λ = 1064 nm a distribution typical of thermal bond breaking is observed. If desorption, however, is stimulated with light of λ = 266 or 532 nm, the kinetic energy distribution is non-thermal with a single maximum atE kin = 0.16 ± 0.02 eV. For λ = 355 nm the non-thermal distribution is even bimodal with maxima appearing atE kin = 0.16 ± 0.02 and 0.33 ± 0.02 eV. These values of the kinetic energies actually remain constant under variation of all experimental parameters. They appear to reflect the electronic and geometric properties of different binding sites from which the atoms are detached and thus constitute fingerprints of the metal surface. The non-thermal desorption mechanism is discussed in the framework of the Menzel-Gomer-Redhead scenario. The transition from non-thermal to thermal desorption at large fluentes of the laser light could also be identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01567319
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Laser-stimulated desorption of potassium atoms (1991)
    Springer
    Applied physics 52 (1991), S. 445-447 
    Details
    ISSN: 1432-0630
    Keywords: 82.65 ; 36.40 ; 73.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Desorption of K atoms by laser-excitation of surface plasmons in small K particles is reported. The desorption rate has been measured for different laser wavelengths and particle sizes. Time-of-flight measurements reveal a kinetic energy of the desorbed atoms of Ekin=0.13(3) eV. From the experimental data it is concluded that the desorption mechanism is non-thermal in nature. Comparison of the results reported here with our earlier work on Na desorption is made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00323657
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Determination of C60/C70 ratios in fullerene mixtures and film characterization by scanning tunneling microscopy (1993)
    Springer
    Applied physics 56 (1993), S. 197-205 
    Details
    ISSN: 1432-0630
    Keywords: 36.40 ; 61.1.P ; 68.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Fullerene powder mixtures with different C60/C70 ratios have been analyzed by a variety of techniques, and results have been compared. The fullerence mixtures have been characterized as solutions in n-hexane by high-pressure liquid chromatography (HPLC) and UV-VIS spectroscopy. Thin films of fullerenes on Au(111) have been prepared from the mixtures by sublimation. The sublimation process has been studied by simultaneous thermogravimetric and differential thermal analyses. Thin fullerene films on Au(111) have been investigated by scanning tunneling microscopy (STM). The STM images show primarily two types of ballshaped molecules arranged in a lattice with hexagonal symmetry (fcc(111) face, nearest neighbour distance: 1 nm). The two species differ in diameter. STM images of films made of mixtures of different C60/C70 ratios show that C70 molecules display a larger apparent diameter (0.8 nm) and corrugation than C60 molecules (0.7 nm). The C60/C70 ratios obtained by counting the corresponding molecular species in the STM images of the thin films are compared to the C60/C70 ratios determined by HPLC on hexane solutions of the mixtures. The observed differences might be explained by different rates of sublimation for the two species. The STM images reveal film defects (vacancies and boundaries) and dynamic processes (displacement of C70 molecules and vacancies). In films prepared to have a C60 coverage of less than one monolayer, stable structural units of the C60(111) surface consisting of three or seven C60 molecules are revealed by STM. Occasionally, substructure within individual fullerene molecules is observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539474
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Role of AWD/Nucleoside Diphosphate Kinase in Drosophila Development (2000)
    Springer
    Journal of bioenergetics and biomembranes 32 (2000), S. 293-300 
    Details
    ISSN: 1573-6881
    Keywords: abnormal wing discs ; lethal mutant ; Drosophila ; Killer-of-prune ; prune
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The abnormal wing discs gene of Drosophila encodes a soluble protein with nucleosidediphosphate kinase activity. This enzymic activity is necessary for the biological function ofthe abnormal wing discs gene product. Complete loss of function, i.e., null, mutations causelethality after the larval stage. Most larval organs in such null mutant larvae appear to benormal, but the imaginal discs are small and incapable of normal differentiation.Killer-of-prune is a neomorphic mutation in the abnormal wing discs gene. It causes dominant lethalityin larvae that lack prune gene activity. The Killer-of-prune mutant protein may have alteredsubstrate specificity. Null mutant larvae have a low level of nucleoside diphosphate kinaseactivity. This suggests that there may be additional Drosophila genes that encode proteinswith nucleoside dipthosphate kinase activity. Candidate genes have been found in theDrosophila genome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005545214937
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    The role of gap junction membrane channels in development (1996)
    Springer
    Journal of bioenergetics and biomembranes 28 (1996), S. 379-385 
    Details
    ISSN: 1573-6881
    Keywords: Development ; gap junctions ; mouse embryos ; Drosophila ; connexin 43 ; transgenic mouse ; neural tube defects ; neural crest cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract In most developmental systems, gap junction-mediated cell-cell communication (GJC) can be detected from very early stages of embryogenesis. This usually results in the entire embryo becoming linked as a syncytium. However, as development progresses, GJC becomes restricted at discrete boundaries, leading to the subdivision of the embryo into communication compartment domains. Analysis of gap junction gene expression suggests that this functional subdivision of GJC may be mediated by the differential expression of the connexin gene family. The temporal-spatial pattern of connexin gene expression during mouse embryogenesis is highly suggestive of a role for gap junctions in inductive interactions, being regionally restricted in distinct developmentally significant domains. Using reverse genetic approaches to manipulate connexin gene function, direct evidence has been obtained for the connexin 43 (Cx43) gap junction gene playing a role in mammalian development. The challenges in the future are the identification of the target cell populations and the cell signaling processes in which Cx43-mediated cell-cell interactions are critically required in mammalian development. Our preliminary observations suggest that neural crest cells may be one such cell population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02110114
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Snowballs of radioactive ions — nuclear spin polarization of core ions (1995)
    Springer
    The European physical journal 98 (1995), S. 347-351 
    Details
    ISSN: 1434-6036
    Keywords: 24.70 ; 36.40 ; 67.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Short-lived ions12B (beta-radioactive, T1/2=20.3 ms) sustaining nuclear spin polarization were introduced into superfluid helium at 1.7 K. It was found that the12B ions were transported as charged entities under a static electric field and that the nuclear polarization was maintained throughout the lifetime of12B nuclei. Polarization of12B was determined through beta-NMR method. “Snowball”, a singly charged microcluster of helium atoms formed around an impurity ion, is responsible for the behaviour and thus constitutes a suitable environment for preserving nuclear polarization of the core ions12B. In a separate experiment snowballs were produced by implanting8Li (T1/2=830 ms) into liquid helium and detected by means of alpha particles from the core ions to guarantee that the snowballs survive longer than the lifetime of12B.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01338403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    The velocity distribution of clusters generated by inert gas condensation (1986)
    Springer
    The European physical journal 1 (1986), S. 131-134 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 07.75
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The velocity distribution of sodium chloride clusters produced by inert gas condensation is determined by means of a mechanical chopping technique. It is found to be the same for all cluster sizes between 1 and more than 200 molecular units per cluster, ruling out the possibility of cluster mass separation by velocity filters. This is explained by an adiabatic expansion occuring during the cluster's exit from the condensation chamber into the high vacuum of the mass spectrometer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384666
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Fragmentation spectroscopy of heterogeneous clusters (1988)
    Springer
    The European physical journal 10 (1988), S. 319-327 
    Details
    ISSN: 1434-6079
    Keywords: 33.65 ; 33.80.E ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photoionisation experiments were performed with heterogeneous Ar-Xe-clusters produced by supersonic expansion of argon gas with small quantities of xenon added to it. A threshold-electron photoionisation (TEPICO) technique was used to obtain time of flight cluster mass spectra. These mass spectra show particularly strong intensities for Ar12Xe+ and Ar18Xe+ which are attributed to the extraordinary stabilities of these cluster ions. Maxima in the ionic size distribution around Ar7Xe+ are related to a particular abundance ofneutral Ar12Xe which is fragmented after ionization. These stabilities are explained in terms of geometries consisting of a central Xe atom or ion surrounded by shells of Ar atoms. Filled shells exhibit particular strong bonding because these exhibit the largest number of atom-atom bonds. This conclusion is supported by simple theoretical calculations. The ionization process is discussed in terms of two direct and one indirect ionization channels the latter one proceeding via an intermediate electronic excitation of the Ar component in the neutral cluster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384867
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    A molecular beam study of a van der Waals complex; vibration-inversion transitions in NH3-Ar (1988)
    Springer
    The European physical journal 10 (1988), S. 291-293 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 33.20.E ; 33.80.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Three ν2 vibration-inversion transitions of NH3-Ar have been found with linewidths smaller than 2 MHz, yielding a minimum predissociation lifetime of 80 ns. While one of these lines was previously identified as a low frequency inversion doublet transition, the other two lines belong to the high frequency component of the ν2 vibration-inversion doublet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384863
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Electronic and atomic structure of Na, Mg, Al and Pb clusters (1988)
    Springer
    The European physical journal 11 (1988), S. 163-174 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Density functional theory is used to study the electronic and atomic structure of small clusters of Na, Mg, Al and Pb. We study the quantityE N−1–E N , which has relevance to the processes of cluster growth and evaporation (E N is the total energy of the cluster withN atoms). By comparing the results of the jellium model with those of a more realistic model (although still simple) we are able to appreciate “structural” effects beyond the “electronic-shell effects” which form the essence of the predictions of the jellium model. The calculations predict formation of atomic shells and appreciable reconstruction as the cluster grows.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01444433
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Stability and structure of singly-charged argon clusters Ar n + ,n=3–27. A Monte-Carlo simulation (1989)
    Springer
    The European physical journal 11 (1989), S. 239-248 
    Details
    ISSN: 1434-6079
    Keywords: 31.20.T ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Monte-Carlo calculations have been performed for positively charged argon clusters in the temperature range between 10 K and 40 K using two different models (one with a dimer ion core, the other one with a trimer ion). The argon-argon interaction potential stems from empirical data, the ion-neutral atoms potential is determined by ab initio MRD-CI calculations. Special stability is found for clusters sizesn=13, 19, 23 and 25/26 atoms using the ‘trimeric core model’ and for those withn=14,n=17,n=20 using the ‘dimeric core model’. The geometrical structure of the clusters is given and the construction principles are discussed in light of the interactions among neutral argon atoms and the ion-neutral atoms interaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01438010
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Exciton absorption and intramolecular Penning ionisation in small molecular clusters I: (N2O)n and C6H5CN·(N2O)n (1988)
    Springer
    The European physical journal 11 (1988), S. 153-162 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photoionisation efficiency (PIE)-spectra are measured for small (N2O)n-clusters,n=2...8, using synchrotron radiation from the electron storage ring BESSY at Berlin. Ionisation thresholds are reported. Resonances in the wavelength-range 97...100 nm forn〉2 are attributed to exciton absorption with N2O-Rydberg levels, series I and II parentage. This interpretation is supported by measurements of the PIE of mixed benzonitrile · (N2O)n clusters where benzonitrile serves as a monitor for photon absorption in N2O at energies above the ionisation limit of benzonitrile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01444432
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    IR predissociation of halogenated methane van der Waals complexes (1988)
    Springer
    The European physical journal 11 (1988), S. 175-180 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 33.80.G ; 35.20.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The infrared dissociation spectra of several halogenated methanes (CHCl2F, CH3F, CF3I and CF3Br) have been studied. Bonded and free C–F stretch excitations have been observed.H-bridges forming the bonding in CHCl2F or CH3F dimers lead to very large red-shifts in the dissociation spectrum with respect to the gas-phase absorptions. Double resonance techniques have been employed to study the homogeneity of the spectral features.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01444434
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Stability of relaxed Lennard-Jones models made of 500 to 6000 atoms (1989)
    Springer
    The European physical journal 12 (1989), S. 85-87 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 61.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a study of the stability of clusters models made of a numberN of atoms in the range 500 to 6000 atoms, freely interacting through the Lennard-Jones potential. The potential energy per atom, calculated for relaxed models, shows that stable models belong to an icosahedral sequence whenN〈1600 and to a decahedral sequence beyond. A coexistence size range of both structures is discussed in connection with experimental results on argon clusters in free jet expansions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426911
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Dynamic and quantum size effects in molecular clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 167-171 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 64.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The evolution of thermodynamic, dynamic and quantum size effects in clusters is expected to contribute towards the merging between microscopic and macroscopic points of view in molecular, surface and bulk phenomena.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426930
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Metal-insulator transitions in microclusters? Mixed sodium/sodium chloride aggregates (1989)
    Springer
    The European physical journal 12 (1989), S. 241-244 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 33.80.E ; 34.80.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photoionization measurements on cluster beams obtained by coexpanding sodium and sodium chloride vapors allow inferences regarding the thermodynamic stability of a number of mixed metal/salt aggregates. We discuss the possibility of observing composition dependent metal/insulator transitions among clusters with a fixed number of monomer units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426947
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Chemisorption and chemical reactions on size selected clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 551-554 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.50 ; L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Low energy ion beam techniques have been used to perform a detailed study of the reactions of Al 25 + and Si 25 + with a range of simple molecules (D2, CH4, O2, C2H4, CO and N2). The reactions were studied over a center of mass collision energy range from 0.2eV up to 7eV. Activation barriers for chemisorption onto the clusters were deduced from the experimental results. The activation barriers for chemisorption on Al 25 + and Si 25 + are generally similar and show a qualitative correlation with the electronic properties of the reactant molecule. However, the products of the chemical reactions of Al 25 + and Si 25 + which result from cluster fragmentation are quite different. Si 25 + shows a tendency to undergo fission as observed in a number of recent studies of the dissociation of the bare clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427016
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Structure of Ag, Fe and Ge microclusters (1989)
    Springer
    The European physical journal 12 (1989), S. 103-105 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 78.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The structures of Ag, Fe and Ge microclusters were determined using EXAFS. The measurements were performed over a wide range of clusters sizes. The clusters were prepared using the gas aggregation technique and isolated in solid argon at 4.2 K. The measurements were performed at the National Synchrotron Light Source (NSLS) at beam line X-18B. A strong contraction of the interatomic distances was observed for Ag dimers and multimers. Silver clusters larger than 12 A mean diameter show a small contraction of thenn distance and a structure consistent with an fcc lattice. By contrast clusters smaller than 12 A show the presence of a small expansion and a strong reduction or absence ofnnn in the EXAFS signal. This points towards a different crystallographic structure for Ag microclusters with diameter less than 12 A. In iron clusters we observe a gradual reduction of thenn distance as the cluster size decreases. The interatomic distance for iron dimers was determined to be 1.94 A, in good agreement with earlier measurements. The iron microclusters show a bcc structure down to a mean diameter of 9 A. Iron clusters with 9 A mean diameter show a structure inconsistent with a bcc lattice. The new structure is consistent with an fcc or hcp lattice. The measurements on Ge clusters show the presence of only nearest neighbors. There was clear evidence of temporal annealing as determined by variations in the near edge structure of the K-absorption edge. Absorption edge measurements were also performed for free Ge clusters travelling perpendicular to the direction of the synchrotron radiation beam. The measurements performed on the free clusters were consistent with those obtained for matrix isolated clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426915
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Ionization dynamics of van-der-Waals clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 253-261 
    Details
    ISSN: 1434-6079
    Keywords: 33.65 ; 33.80E ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ionization process of homogeneous and heterogeneous van-der-Waals clusters has been investigated using various ionization methods (electron bombardment, charge exchange, photoionization methods), and different analyzing techniques. Direct and indirect ionization processes can be distinguished in the experiments from the shape of the ionization curve which depends on the type of cluster. These features appear differently in homogeneous and heterogeneous systems: Homogeneous systems exhibit characteristic ionization efficiency curves where the direct ionization path appears as a sudden increase in the ionization efficiency while the indirect transition gives rise to a long drawn out tail extending to the true ionization threshold. In heterogeneous clusters the indirect ionization path proceeds via excited states of the component with the larger ionization potential and subsequent energy transfer to the other component. These transitions are shifted and broadened depending on the type of internal interaction. Conclusions are drawn concerning the geometry and the interaction potential inside the cluster. The resolution of the TEPICO (Threshold Electron Photo Ion Coincidence) experiments makes it possible to determine the kinetic energy release of the fragments. It is shown that the results are related to the stabilities of the cluster ions involved in the fragmentation chain. Results are presented for pure rare gas clusters (Ar n , Kr n , Xe n ) and for mixed systems (Ar n O2m , Ar n Xe, Kr n Xe, (CH4) n Ne).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426950
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Observation and investigation of metastable decay series of (N2) n + cluster ions (1989)
    Springer
    The European physical journal 12 (1989), S. 285-287 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.80.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract N2 cluster ions are produced by electron impact ionization of a supersonic N2 cluster beam and analyzed with a double focussing sector field mass spectrometer. It is found that metastable N2 cluster ions lose more than one N2 molecule in the μs time regime and decay predominantly via sequential series (N2) n + *→(N2) n−1 + *→...→N 2 + , evaporating a single monomer in each of these successive decay steps. The metastable decay rates determined in detail for cluster sizes 2≤n≤6 andn=20 lie between 1 and 106s−1. These rates(i) depend strongly on the time elapsed after ion formation and on the respective parent cluster ion size, and(ii) exhibit a quasiperiodic pattern in magnitude.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426957
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Electron bombardment fragmentation of size selected molecular clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 293-295 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.40 ; 34.80.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract (CO2) n , (NO) n and (NH3) n clusters are generated in a supersonic molecular beam and size selected by scattering from an He beam. By measurements of angular dependent mass spectra, TOF distributions and the angular dependence of the scattered signal quantitative information on the fragmentation probability by electron impact is derived. The van der Waals systems (CO2) n and (NO) n appear only at masses which are simply multiples of the monomer mass. The preferred cluster ion is the monomer ion for all investigated cluster sizes withn=2 to 4. The fragment pattern for the quasi-hydrogen bonded (NH3) n -cluster shows, beside a large number of fragment masses, a preference for protonated ions. The results are explained in terms of simple models based on the structural change from the neutral to the ionized configuration and the fragmentation pattern of the monomer followed by ionmolecule reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426960
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Kinetic energy release of clusters after multiphoton ionisation with time of flight and electrostatic analyser techniques (1989)
    Springer
    The European physical journal 12 (1989), S. 297-301 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 32.80.K
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new technique is presented which allows direct observation of initial kinetic energies in multiphoton ionisation-fragmentation processes of molecules and clusters and provides an unambiguous determination of metastable decay channels. Results are presented for the unimolecular loss of a monomer from clusters (C6H6) 8 + to (C6H6) 12 + and for the reaction C6H 6 + →C4H 4 + +C2H2. We also observe a significant amount of probably collision induced fragmentation processes (C6H6) n + →(C6H6) n−x + + (C6H6) x withx much larger than 1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426961
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Electronic structure of metal clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 319-326 
    Details
    ISSN: 1434-6079
    Keywords: 79.60 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photoemission spectra of valence electrons in metal clusters, together with threshold ionization potential measurements, provide a coherent picture of the development of the electronic structure from the isolated atom to the large metallic cluster. An insulator-metal transition occurs at an intermediate cluster size, which serves to define the boundary between small and large clusters. Although the outer electrons may be delocalized over the entire cluster, a small cluster remains insulating until the density of states near the Fermi level exceeds 1/kT. In large clusters, with increasing cluster size, the band structure approaches that of the bulk metal. However, the bands remain significantly narrowed even in a 1000-atom cluster, giving an indication of the importance of long-range order. The core-electron binding-energy shifts of supported metal clusters depend on changes in the band structure in the initial state, as well as on various final-state effects, including changes in core hole screening and the coulomb energy of the final-state charge. For cluster supported on amorphous carbon, this macroscopic coulomb shift is often dominant, as evidenced by the parallel shifts of the core-electron binding energy and the Fermi edge. Auger data confirm that final-state effects dominate in cluster of Sn and some other metals. Surface atom core-level shifts provide a valuable guide to the contributions of initial-state changes in band structure to cluster core-electron binding energy shifts, especially for Au and Pt. The available data indicate that the shift observed in supported, metallic clusters arise largely from the charge left on the cluster by photoemission. As the metal-insulator transition is approached from above, metallic screening is suppressed and the shift is determined by the local environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426965
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    The relationship of Au55(PPh3)12Cl6 to colloidal gold (1989)
    Springer
    The European physical journal 12 (1989), S. 533-536 
    Details
    ISSN: 1434-6079
    Keywords: 33.20.K ; 35.20.G ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The electronic (UV-visible) spectrum of the molecular cluster Au55(PPh3)12Cl6 shows features corresponding to the 520 nm plasma resonance and the shorter-wavelength interband transition of colloidal gold. These absorptions differ qualitatively from the simpler one-electron transitions of lower-nuclearity cluster molecules. Differential scanning calorimetry has been used to measure the enthalpy of decomposition of Au55(PPh3)12Cl6. The Au-Au bonding appears to be substantially stronger than in bulk gold.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Reactivity of free clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 537-541 
    Details
    ISSN: 1434-6079
    Keywords: 82.30 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recent studies of the reactions of free or isolated transition metal clusters with simple molecules will be reviewed. Cluster chemical reactions are carried out in a laser-vaporization cluster source coupled to a continuous-flow reactor. Reactions can be categorized as chemisorptive (or surface) reactions, and bulk reactions. Chemisorptive reactions can be characterized asfacile, in which most cluster sizes of a given metal are equally reactive towards a particular reagent, oractivated, in which strong dependence of reactivity on cluster size is found. Under the normal operating conditions of the cluster reactor, a reaction may be kinetically controlled or at equilibrium. Following chemisorption, adsorbate decomposition and product desorption may occur. Specific reactions to be discussed include the reactions of iron clusters with ammonia and with water and the reactions of nickel clusters with ammonia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427013
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Reaction of Aln clusters with oxygen and ammonia (1989)
    Springer
    The European physical journal 12 (1989), S. 571-573 
    Details
    ISSN: 1434-6079
    Keywords: 82.30 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Aluminum clusters were generated by a laser vaporization method. Ionization potential of Al2 was found to be lower than that of Al. In the reaction with oxygen at high concentration, the mixed cluster Al9O7 survives predominantly as a stable cluster. Ammonia was found to be adsorbed weakly on the Aln surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427020
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Influence of the precursors on the properties of alumina supported rhodium particles (1989)
    Springer
    The European physical journal 12 (1989), S. 579-582 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The effect of chlorine on the properties of Rh particles supported on alumina was studied using the hydroconversion of alkanes as a molecular probe. Chloride ions on the alumina have little influence on the Rh particles. Chlorine adsorbed on the Rh particles decreases the chemisorption capacity and increases the metal-support interaction, which results in modifications of their catalytic properties. Depending on the alkane processed, specific activity can be depressed up to four orders of magnitude.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427022
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Influence of dispersion on the energies of adsorption: H2, CO, propylene and propyne on supported Pd or Pt (1989)
    Springer
    The European physical journal 12 (1989), S. 583-586 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 82.65.Jv ; 82.60.Cx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The aim of this work is to contribute to an explanation of thelowering of the specific activity of Pd/Al2O3 catalysts, towards hydrogenation of acetylenic molecules,as the dispersion increases. For this purpose, the interaction energy between these catalysts and H2, CO, propylene and propyne was directly measured by adsorption microcalorimetry at 323 K. In the case of propyne, the enthalpy of adsorption was found to be more than 50% higher for the catalysts with 97% dispersion than for the one with 26% dispersion, for coverages ranging from 0.2 to 0.7.This high enthalpy of adsorption (up to 290 kJ.mol−1) is attributed to a different proportion of edges and crystalline planes in the smallest Pd crystallites and is indeed consistent with a “blocking”chemisorption or with a hindered desorption of the products of a catalytic hydrogenation, i.e. with a lowering of the specific activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427023
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Laser induced fission of C60 with kinetic energy release (1992)
    Springer
    The European physical journal 24 (1992), S. 307-309 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 33.80 ; 33.80.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A neutral C60 fullerene beam is ionised by 308 nm laser pulses. For each cluster sizeC n + , 0〈n≦60 of the typical bimodal mass distributions known from the literature [1] velocity distributions have been determined by a time of flight method. A consistent interpretation of the measured mean velocities is obtained when binary fission of the parent molecule is assumed to be responsible for the fragmentation patterns, the total kinetic energy release being 0.45±0.1 eV independent of fragment mass and of laser fluence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426677
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Excitation and decay processes in helium clusters studied by fluorescence spectroscopy (1993)
    Springer
    The European physical journal 26 (1993), S. 175-177 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 67.90+Z ; 71.90+Q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Excitation and decay processes of helium clusters are investigated with fluorescence methods. The results differ remarkably from that obtained for the heavier rare gas clusters. They are discussed in view of the unusual structural and electronic properties of helium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429135
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Symmetry substructures for MQ-NMR of [A]20 spin clusters of dodecahedranes, [13CH]20 or [13CD]20, metallic M @M20 and [H2O]+ @[H2O]20 exo-cage cluster molecules and their higher-n SO(3) ×l n spin algebras, within the context of mapping,l n -ITP algebras and number partitions (1993)
    Springer
    The European physical journal 25 (1993), S. 275-284 
    Details
    ISSN: 1434-6079
    Keywords: 76.60 ; 03.65.F ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract For both highern andI i ≧1 spin clusters, combinatorics provides powerful arguments with which to investigate the substructural forms of cluster spin algebras; this is especially so for SO(3) ×l n symmetries for 12≦n≦60 wherex (.) [λ] character tabulations become extensive. Bijective enumerative mappings over the combinatorialp-tuples (number partitions) afford insight into the general functionf(p,n) as well as into {|IM(I 1−I n [λ]〉} M -structure of spin algebras, even where the full details of the explicitx () [λ] (l n ) characters are not readily available. Both simply-reducible and higher aspects ofl n -inner tensor product (ITP) algebras are derived from dimensionality considerations, as part of combinatorial hooklength formalisms for $$\chi _{(1^n )}^{[\lambda ]} $$ . TheI i ≦3/2 forms of [A] n clusters forn≦20, (forp≦3, 4) of multiple-quantum NMR (MQ-NMR) are considered here as part of current interest in giant cage-clusters. In addition, the SU2 substructural hierarchy over Liouville space is derived for [A]20(l n ) (I i =1/2) spin cluster of the cage-cluster molecule dodecahedrane; aspects ofI i =1 spin cluster over {|IM (...)〉} space are derived as high temperature model of the exo-cage of [H2O]+ @[H2O]20 cluster ion; 20-fold higher-I i lusters provide models for M @M20 metal-clusters and further applications ofl 20-number partitions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426891
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Structural transitions and melting of copper clusters (1993)
    Springer
    The European physical journal 26 (1993), S. 255-257 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Molecular dynamics is used to study the melting and structural transitions of small copper clusters. The melting temperature is found to be proportional to the average coordination number. Small icosahedral clusters melt at slightly higher temperatures than the cubic structures. Small cuboctahedral clusters are not stable but transform via a nondiffusive transition to icosahedral structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429161
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Nuclear shell model applied to metallic clusters (1993)
    Springer
    The European physical journal 26 (1993), S. 261-263 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We apply the nuclear shell model to jellium clusters of up to twenty-one Na atoms. Binding energies, ionization potentials, and photoabsorption cross sections are calculated and compared with mean-field results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429163
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    The evolution of electronic structure in AlnCom (1993)
    Springer
    The European physical journal 26 (1993), S. 322-324 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 33.80.E
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ionization potentials of AlnCom clusters (n〉m) have been bracketed using laser photoionization mass spectrometry. We find the electronic shell structure manifested in the ionization potentials of Aln for n≥7 is observed also for AlnCo and AlnCo2, and is consistent with cobalt contributing one electron to the conduction band of the cluster. However, with increasing number of cobalt atoms, this simple picture breaks down; all vestiges of aluminum cluster electronic shell structure are absent for m≥4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429182
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Molecular dynamics studies of homogeneous nucleation in solid-state transitions (1993)
    Springer
    The European physical journal 26 (1993), S. 364-366 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 64.60.Qb ; 64.70.Kb ; 82.20.Wt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Simulations of clusters containing 100 to 250 molecules of TeF6 successfully reproduce the crystalline packing arrangements observed in electron diffraction investigations of large molecular clusters (∼ 104 molecules) of the same material. More remarkably, when the clusters are cooled step by step in MD computations at a rate of ca. 1011 K/s they spontaneously undergo the same bcc to monoclinic phase transition that has been observed experimentally in supersonic flow, despite the million-fold difference in the timescales involved. The existence of such a correspondence over so many orders of magnitude, in itself, imposes severe constraints on what type of molecular mechanism can underlie the transformation. Even more revealing evidence about the molecular behavior associated with the phase change is provided by the simulations. They show the formation of the actual transition complexes along the transition pathway, namely, the critical nuclei of the new phase. These nuclei, which are made up of approximately 20 molecules, can be recognized in the midst of the surrounding matter. Techniques based on molecular orientations, involving Pawley-Fuchs projections and orientational angular distribution functions, make it possible to estimate the size of critical nuclei. One noteworthy result established in the simulations is that the solid-state transition temperature from bcc to monoclinic depends upon particle size in the same manner as does the freezing point.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429196
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Excitation and decay processes in helium clusters studied by fluorescence spectroscopy (1993)
    Springer
    The European physical journal 26 (1993), S. 382-384 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 67.90+Z ; 71.90+Q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Excitation and decay processes of helium clusters are investigated with fluorescence methods. The results differ remarkably from that obtained for the heavier rare gas clusters. They are discussed in view of the unusual structural and electronic properties of helium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Characterization of the fluxes of neutral and positively charged clusters (Agn and Ag n + ; n≤4) produced by argon ion sputtering of silver (1993)
    Springer
    The European physical journal 26 (1993), S. 101-103 
    Details
    ISSN: 1434-6079
    Keywords: 79.20N ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The emission of neutral and positively charged silver clusters during sputtering of a polycrystalline silver target by 5 keV Ar+ ion bombardment has been studied and the sputter ejected silver flux has been characterized. As a result, the silver flux is found to be strongly dominated byneutral clusters rather than cluster ions. The contribution of neutral clusters in the overall silver flux decreases rapidly and monotonically with increasing cluster size n and decreases, in addition, with decreasing bombarding energy. The well known alternation of the secondary ion intensities of Ag n + as a function of cluster size (higher intensities for odd n) is found to be correlated with the effective “ionization potentials” of the corresponding sputtered neutral clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425631
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Melting behavior of beryllium clusters (1993)
    Springer
    The European physical journal 26 (1993), S. 134-136 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The melting properties of Ben, n=7−14, clusters have been studied using molecular dynamics simulations and an interatomic potential which contains two- and three-body terms, derived from local spin density calculations. The cluster meltinglike behavior has been studied calculating characteristic physical quantities like short-time averages of the kinetic energy per particle as a function of time, caloric curves and root-mean-square bond length fluctuations as a function of the cluster total energy. The meltinglike transition in Ben clusters shows more complex features than those found in van der Waals and ionic clusters. The estimated melting temperatures for n=11−14 are higher than the bulk value. This result indicates that the parameters of the cluster interaction potential could be inadequate to describe the thermodynamic properties of Ben clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425642
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Interaction of CO with silver clusters: Dependence on cluster size (1993)
    Springer
    The European physical journal 26 (1993), S. 162-164 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The interaction of matrix-isolated silver clusters with CO has been investigated for clusters containing as few as 100 atoms/cluster. A vibrational mode at a monolayer coverage, which is found on bulk silver at 2110 cm−1, is present even for these small particles. For these small-sized particles however, an additional, broad, unresolved band at 1950 cm−1 appears, which does not exist for larger clusters. Whether this band has its origin in a modified chemical behaviour for particles smaller than 100 at/cl is not clear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425651
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    The formation and photolysis of tantalum sulfide cluster ions (1993)
    Springer
    The European physical journal 26 (1993), S. 246-248 
    Details
    ISSN: 1434-6079
    Keywords: 82.30.N ; 36.40 ; 82.50.F
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Tantalum sulfide cluster ions were produced by direct laser ablation, and were studied with a tandem time-of-flight mass spectrometer. The main dissociation channel of the UV-photolysis (248 nm) of tantalum sulfide cluster ions is sequent S2 loss. Structures with Ta3S4 and Ta4S6 as frameworks were suggested for the large tantalum sulfide cluster ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425679
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Ring-stacking consideration on higher fullerene growth (1993)
    Springer
    The European physical journal 26 (1993), S. 258-260 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A hypothetical ring-stacking procedure combined with the isolated-pentagon rule(IPR) shows variety of formation pathways of many fullerene structures with a 5- and 6-membered ring carbon cage. Combining the ring-stacking procedure with energetic considerations, the numbers of possible reaction channels are dramatically reduced within the framework of the ring-stacking considerations. This, in turn, gives the results that only some specific isomers of large fullerenes are selectively produced. The resulting fullerene structures specified are surprisingly well consistent with the recent experimental results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425683
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Electronic and geometrical structure of noble metal clusters (1993)
    Springer
    The European physical journal 26 (1993), S. 12-14 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the electronic and structural properties of small (N ≲ 20) and medium sized (N ≲ 500) clusters of Cu, using the first principles Tight-Binding Linear Muffin-Tin Orbitals (TB-LMTO) method in connection with the real-space recursion scheme. We find the electronic structure resembling the one of simple alkali metal clusters: Pronounced shell closing effects can be identified in the ionization potentials as well as in the HOMO-LUMO gaps for the magic sizesN=8, 20, 34 and 40. The low-energy equilibrium geometries show considerable Jahn-Teller distortions, just as in the case of alkali metals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425602
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Electron energy loss spectroscopy of free C60 and C70 (1993)
    Springer
    The European physical journal 26 (1993), S. 294-296 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Electron energy loss spectroscopy has been performed with samples of pure C60 and C70 using primary electron energies between 10 and 1100 eV. The experimental data could be explained in terms of optically forbidden and allowed transitions, and by collective excitations (plasmons), which could be distinguished by their dependence on the energy of the primary electron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425695
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Reactivity of carbon cluster ions with Ar, O2 and D2 (1993)
    Springer
    The European physical journal 26 (1993), S. 305-307 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 35.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Carbon cluster ions generated by laser evaporation have been reacted with atoms (Ar) and molecules (O2, D2). In order to vary the reaction conditions for the cluster ions two gas inlets at different locations have been added to the cluster source. Addition of D2 increased the line width in the TOF-spectrum indicating the appearance of reaction products of the type CmDn. Both O2 and D2 proved very effective in removing the odd numbered carbon cluster ions in the vicinity of C60. Application of O2 produced a significant effect: depending on the gas pressure it reacted with small cluster ions forming products like CnO+ and CnO2 +. Such reaction channels are not found for n〉12 thus indicating a change in cluster geometry. Another sequence of experiments has been undertaken by adding Ar atoms to the carbon cluster ions. Some stable ionic reaction products like ArC+,..., ArC4 +, ArC5 + can be detected. It is known from previous studies that the ArC+ is a stable ion with an dissociation energy of about 1 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425698
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Dynamics of cluster-surface interaction: Evidence of structural isomers of C 60 − (1993)
    Springer
    The European physical journal 26 (1993), S. 320-322 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Collision induced electron detachment of the fullerene C 60 − and the other C 60 − produced through the laser vaporization of a carbon rod was studied. Both of C 60 − showed quite different behavior for the process. It was suggested that the laser vaporized C 60 − has a different structure from the fullerence C 60 − .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425703
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Quantum mechanical study of the structure and stability of molecular van der Waals' clusters II: (NH3)nHCN (1993)
    Springer
    The European physical journal 26 (1993), S. 329-331 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20.D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The structures and stabilities of small mixed clusters of ammonia with hydrogen cyanide have been studied usingab initio electronic structure calculations at the Hartree Fock and Møller Plesset levels of theory. Stable structures for (NH3)nHCN, n=1, 2, 3 have been located. Two stable structures and a transition state for the heterodimer are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01425706
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Atomic and molecular impurities in4He clusters (1994)
    Springer
    The European physical journal 29 (1994), S. 61-66 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 67.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A density functional theory is used to predict the binding energy of atomic and molecular impurities (Ne, Ar, Kr, Xe, Li, Na, K, Rb, Cs, and SF6) in the center of4He clusters, in the limit of zero temperature and for zero angular momentum states. The size dependence of the binding energy, from small clusters to the bulk liquid limit, is investigated. The behaviour of the4He density near the impurity is also studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437166
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    On the history of cluster beams (1986)
    Springer
    The European physical journal 3 (1986), S. 101-107 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The methods to produce and investigate cluster beams have been developed primarily with the use of permanent gases. A summary is given of related work carried out at Marburg and Karlsruhe. The report deals with the effect of carrier gases on cluster beam production; ionization, electrical acceleration and magnetic deflection of cluster beams; the retarding potential mass spectrometry of cluster beams; cluster size measurement by atomic beam attenuation; reflection of cluster beams at solid surfaces; scattering properties of4He and3He clusters; the application of cluster beams in plasma physics, and the reduction of space charge problems by acceleration of cluster ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384793
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    The formation and kinetics of Ionized Cluster Beams (1986)
    Springer
    The European physical journal 3 (1986), S. 137-142 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 47.55E ; 68.55.tb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The formation and kinetics of large vapourized-material cluster beams (large size metal clusters) are discussed. The clusters are formed by injecting the vapour of solid state materials into a high vacuum region through a nozzle of a heated crucible. The conditions under which metal clusters form are analysed using nucleation theory. Computer simulation by combining the nucleation and flow equations has also been made. The results show that the theory can be useful in predicting qualitative dependences of metal cluster formation on operation conditions. Several experimental results are also presented, which support the finding that a large size metal cluster is formed by homogeneous nucleation and growth. The advantageous characteristics of ionized cluster beam for thin film formation are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384798
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Analysis of the reactivity of small cobalt clusters (1986)
    Springer
    The European physical journal 3 (1986), S. 205-209 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The electronic structures of small cobalt clusters have been calculated within the local spin density approximation using the LCAO method. The calculations were done for simple geometries with the optimized number of interatomic bonds, and both for the bond length of the cobalt dimer and the bulk metal. The Fermi energy is found to be smaller for Co N clusters withN=3, 4, 5 andN〉10 than for the other ones. The variation of the Fermi energy with the cluster size correlates in a striking way with the observed H2 tendency for chemisorption as found for cobalt clusters in a supersonic beam. Furthermore, the magnetic moments are somewhat smaller for these active clusters. In addition the lowest unoccupied levels of majority spin appear close to the highest occupied levels of minority spin which is not the case for the inert clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384808
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Orientation dependence in collision induced electronic relaxation studied through van der Waals complexes with isomeric structures (1994)
    Springer
    The European physical journal 31 (1994), S. 105-115 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.30 ; 34.20.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Weakly bound molecular complexes with more than one well-defined structures provide us with an unique opportunity to investigate dynamic processes induced by intermolecular interactions with specific orientations. The relative orientation of the two interacting molecules or atoms is defined by the complex structure. The effect of the orientation in the spin changing collisions glyoxal(S1)+Ar → glyoxal(T1)+Ar and acetylene (S1)+Ar → acetylene(T)+Ar have been studied by measuring the intersystem crossing (ISC) rates of the glyoxal(S1)·Ar and acetylene(S1)·Ar complexes with different isomeric structures. Results show that there is a strong orientation dependence in the ISC of glyoxal(S1) induced by interaction with the Ar atom: the Ar atom positioned in the molecular plane is much more effective than in the out-of-plane position in inducing the S1 → T1 transition of glyoxal. On the other hand, studies of acetylene(S1)·Ar complexes indicate that the Ar-induced ISC rates are nearly identical for the in-plane and out-of-plane positions. Orientation dependence in the collision induced vibrational relaxation process C2H2(S1,v i )+Ar → C2H2(S1,v f 〈v i )+Ar is also studied by measuring the vibrational predissociation rates of the acetylene(S1)·Ar complex isomers. The results indicate that collisions of C2H2(S1,v 3=3, 4) with Ar at two orthogonal orientations are equally effective in causing vibrational relaxation of C2H2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426585
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Effects of the cluster surface on the electronic shell structure: faceting, roughness and softness (1994)
    Springer
    The European physical journal 31 (1994), S. 253-258 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Several simple models have been used to study the effects of the surface on the electronic shell structure in metal clusters. The main results are as follows: The icosahedral clusters have the same electronic shell structure as the sphere up to about 1000 atoms. The surface roughness causes the distribution of the level spacings to be a Wigner distribution. By varying the softness of the potential we can obtain potentials where the simplest classical orbits are the ‘five-point star’ or even the ‘three-point star’.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01445003
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Fission barriers for Na N 2+ cluster dissociation (1994)
    Springer
    The European physical journal 31 (1994), S. 275-277 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.15 ; 31.20.S ; 31.90
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The competition experimentally observed between asymmetric fission and neutral monomer evaporation as dissociation channels of excited doubly charged sodium clusters has been investigated by means of an axially symmetric, fully selfconsistent Kohn-Sham method. Ellipsoidal equilibrium configurations for parent and daughter clusters have been considered using a deformed jellium model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01445006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Dipole excitation of Na clusters with a non-local energy density functional (1994)
    Springer
    The European physical journal 31 (1994), S. 283-286 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20 ; 71.45
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The elementary dipole excitations of the ionized clusters Na 9 + , Na 21 + and Na 41 + are investigated by solving the equations of the Random-Phase Approximation. The ground and excited states are described using the jellium model for the ionic background and a non-local energy density functional for the valence electrons. Non-local effects are specifically analyzed. The excitation energies thus obtained approach better than those of the Local Density Approximation both the full Hartree-Fock and the experimental results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01445008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Energy transfer in collisions of alkali-metal clusters and ions (1995)
    Springer
    The European physical journal 33 (1995), S. 289-293 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The electronic energy loss of a positively charged projectile passing through a sodium cluster is calculated by the semiclassical Vlasov method. The electron density before impact is obtained within the localdensity approximation in the jellium model. For the dynamical response, the Vlasov equations are solved by test particle discretization. The model gives the correct breathing mode and dipole Mie frequencies. The energy deposit is calculated as a function of projectile velocity, charge and impact parameter and is compared with theoretical and tabulated values for bulk sodium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437509
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Condensation in free jets: Comparison of rare gases and metals (1987)
    Springer
    The European physical journal 4 (1987), S. 291-299 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 51.30 ; 64.90
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In view of the recent interest in metal cluster beams obtained from free jet expansions, the paper extends the scaling laws and similarity relations developed for rare gases to metal vapors. The enthalpy of evaporation at 0 K and the density of the solid are used to define for both metals and rare gases, a species-characteristic temperature and length,T ch andr ch. This allows to transform the scaling parameter for condensation of a given gas,π=n 0·d q·T 0 (0.25q-1.5) , into a reduced scaling parameter π* by replacingn 0,d andT 0 by their respective reduced termsn*=n·r ch 3 ,d*=d/r ch, andT*=T/T ch. As shown before for the rare gases, free jets with the same π* are similar with respect to cluster formation. Based on an analysis of existing experimental data in terms of the respective π*, onset of condensation of metals in free jets is correlated by π* too. For π*〈200 the free jets do not produce clusters, while for π*〉1,000 clusters exceeding 100 atoms/cluster are being observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01436638
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    First-principle calculations ofK-edge X-ray absorption spectra for small iron and nickel clusters (1989)
    Springer
    The European physical journal 13 (1989), S. 153-159 
    Details
    ISSN: 1434-6079
    Keywords: 31.20 ; 36.40 ; 78.70.D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this study we present theoretical X-ray absorption near-edge spectra (XANES) evaluated for Fe2, Ni2, and Ni3 using a modified multiple-scattered wave procedure. The calculations were performed for different internuclear distances of the dimers and by varying the geometry from linear to equilateral triangular for Ni3. The calculated absorption spectra for both Fe2 and Ni2 predict a broad resonant structure at the threshold and weak 1s transitions to unoccupied valence orbitals −5→0 eV giving a shoulder at the threshold. The resonance structure at the threshold of Ni3 appeared to be sensitive to the geometry of the clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01398585
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Fission of ionized alkali metal clusters (1990)
    Springer
    The European physical journal 17 (1990), S. 57-60 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study the symmetric fragmentation of ionized alkali clusters within a liquid-drop type model. The interplay of surface and Coulomb interactions leads to a stability condition against small deformations which depends on the ratioZ 2/N. For systems which are stable against small-amplitude oscillations we consider the possibility of large-amplitude modes eventually leading to fission and give in terms of the same quantity an estimate of the potential barrier for this fission channel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437498
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    The smoke ion source: a device for the generation of cluster ions via inert gas condensation (1989)
    Springer
    The European physical journal 12 (1989), S. 3-6 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.80G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report the development of an ion source for generating intense, continuous beams of both positive and negative cluster ions. This device is the result of the marriage of the inert gas condensation method with techniques for injecting electrons directly into expanding jets. In the preliminary studies described here, we have observed cluster ion size distributions ranging fromn=1−400 for Pb n + and Pb n − , and fromn=12−5700 for Li n − .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426893
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Structural fluctuation and atom-permutation in transition-metal clusters (1989)
    Springer
    The European physical journal 14 (1989), S. 247-261 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The atomic structure and thermodynamic properties of transition-metal clusters containingN atoms are investigated forN=6 and 7 using the method of molecular dynamics, where Gupta's potential taking into account many-body interaction is employed. The caloric curve (total energy — temperature curve) and the structural fluctuations are studied. The “fluctuating state” is found forN=6 in the region of the temperature near below the melting point, where clusters undergo structural transition from one isomer to others without making any topological change. The fluctuating state differs from the coexistence state in that the former involves no atomic diffusion, and goes to a structural phase transition of the bulk whenN is increased. On the other hand, the motion of atom-permutation is found in the low-temperature region of the liquid state, being induced by the cooperative motion of two atoms. It is discussed that such a motion easily occurs along the surface and may be considered to be one of the characteristics of small clusters. The fluctuating state is discussed in relation to the structural fluctuation of gold clusters observed experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437325
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Investigation of the stabilities of neutral and ionic lead and lead-antimony clusters under single and multiphoton ionization conditions (1989)
    Springer
    The European physical journal 14 (1989), S. 353-360 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 33.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The fluence dependence of lead cluster ion distributions at 222 nm and 308 nm reveal markedly different behavior. Results obtained at 308 nm display a simple uniform increase in intensity with higher laser fluence with little change in relative intensities. At 222 nm, however, a significant transformation is found from a markedly different low fluence distribution to a high fluence pattern, which is essentially indistinguishable from that observed at 308 nm. It is concluded that mass spectra obtained at 308 nm, regardless of fluence, or at 222 nm and high fluence contain appreciable contributions from fragmentation. Hence, under these conditions the mass spectra are found to be dominated by cluster ion stabilities. Magic numbers observed at both high and low fluence correspond well to those obtained using electron-impact ionization, and in many instances parallel the magic numbers characteristic of rare-gas clusters. This suggests the stabilities of both neutral and monovalent cationic lead clusters are largely determined by close-packing considerations, and are not appreciably influenced by electronic structure. Similar preferences for close-packed structures are also found for mixed lead-antimony clusters containing one or two antimony atoms that are ionized using high fluence 308 nm excitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429285
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Coulomb explosion of charged jellium clusters (1989)
    Springer
    The European physical journal 11 (1989), S. 323-326 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Density Functional Formalism is used to calculate the minimum number of atoms (N c ) a multiply charged jellium-like spherical cluster must contain to be stable against coulomb explosion into two smaller fragments. In the case of alkaline clusters, which are systems for which the jellium model can be applied, we findN c equal to 31 and 23 for the explosion of Na N 2+ and Cs N 2+ respectively, in good agreement with the experimental value ofN c = 18 for Cs N 2+ . Calculated critical numbers for triply and tetracharged Cs clusters are 108 and 323 respectively. In addition the model predicts that the most favourable fragmentation channel is the ejection of a singly charged monomer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01438506
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Enrichment and segregation in alkali heteroclusters (1989)
    Springer
    The European physical journal 12 (1989), S. 237-239 
    Details
    ISSN: 1434-6079
    Keywords: 31.20 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A spherical average pseudopotential method (SAPS) is used to investigate some properties of compound alkali clusters. The effect that the substitution of a Sodium atom by a Lithium atom in a Na n cluster has on the stabilities and geometries is studied forn≤21. We have found that substitution is always energetically possible. On the other hand equiatomic Na n Cs n clusters are considered in the size rangen≤16. We find a strong segregation effect of the Cesium atoms towards the cluster surface. This agrees with what happens in liquid Na x Cs1−x alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426946
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Sodium halide clusters: evidence for direct electronic fragmentation (1989)
    Springer
    The European physical journal 12 (1989), S. 249-251 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.80 ; 33.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Sodium halide clusters are generated by inert gas condensation and probed by electron and photon induced dissociation. The dependence of fragmentation on electron energy and initial cluster temperature indicates a direct electronic fragmentation process without an intermediate state of vibrationally hot clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426949
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Intra-cluster ion-molecule reactions and photodissociation of molecular clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 269-271 
    Details
    ISSN: 1434-6079
    Keywords: 33.80.E ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Intra-cluster ion-molecule reactions in benzene clusters and benzene-water binary clusters were observed in Resonance-Enhanced Multi-Photon Ionization (REMPI) Time-of-Flight (TOF) mass spectra. Condensation reactions of the excited dimer unit or higher cluster unit are found to occur within clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426952
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Metastable decay of rare gas cluster ions: mechanism and kinetics (1989)
    Springer
    The European physical journal 12 (1989), S. 263-267 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.80.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Metastable decay of cluster ions has been discovered only recently. It was noted that one has to take this metastable decay into account when using mass spectrometry to probe neutral clusters, because ion abundance anomalies in mass spectra of rare gas and molecular clusters are caused by delayed metastable evaporation of monomers following ion production. Moreover, it was found that(i) the individual metastable reaction rates k depend strongly on cluster size and cluster ion production pathways and that(ii) there exists experimental evidence (k=k(t)) and a theoretical prediction that a given mass selected cluster ion generated by electron impact ionization of a nozzle expansion beam will comprise a range of metastable decay rates. In addition, it was discovered that metastable Ar cluster ions which lose two monomers in the μs time regime decay via sequential decay series Ar n + *→Ar n−1 + *→Ar n−2 + * with cluster sizes 7≤n≤10 andn=3 (similar results were obtained recently in case of N2 cluster ions). Conversely, the dominant metastable decay channel of Ar 4 + * into Ar 2 + was found to proceed predominantly via a single step fissioning process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426951
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Multiply charged cluster ions of Ar, Kr, Xe, N2, O2, CO2, SO2 and NH3: Production mechanism, appearance size and appearance energy (1989)
    Springer
    The European physical journal 12 (1989), S. 279-281 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 07.75
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Clusters of Ar, Kr, Xe, N2, O2, CO2, SO2 and NH3 formed by supersonic nozzle expansion have been studied by electron impact ionization mass spectrometry (up to 15000 amu). Besides mass spectra of singly charged ions showing the characteristic anomalous distributions, we have in particular investigated the properties of multiply charged cluster ions. Critical appearance sizes of doubly and triply charged cluster ions, n2 and n3 respectively, found in the present study confirm recent theoretical predictions about n3/n2 and their dependence on the properties of the cluster constituents. The appearance energies of multiply charged cluster ions determined are shifted way below the appearance energies of the respective monomer ions. These huge red shifts together with the observed linear threshold laws and large maximum ionization efficiencies indicate that multiply charged cluster ions are produced by sequential single ionization events of one incoming electron at different cluster sites. Furthermore, we have also obtained for the first time clear evidence that (for electron energies above the appearance energy of doubly charged ions) an appreciable amount of singly charged (also fragment) ions is produced via Coulomb explosion of unstable doubly charged ions in the ion source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426955
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    A mechanism of electron attachment to small clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 291-292 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.50.H ; 34.80.D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Van der Waals clusters of various molecules were collisionally ionized by high-Rydberg rare gas atoms and slow electrons. Negative cluster ions thus produced were detected by mass spectroscopy. The ionization mechanism were investigated by measurements of the size- and the energy-dependences of the electron attachment cross sections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426959
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Interactions of electrons with SF6: ionization and attachment (1989)
    Springer
    The European physical journal 12 (1989), S. 303-305 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 34.80.G
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Electron attachment and electron impact ionization of SF6 clusters have been investigated quantitatively in a molecular beam/electron ion source/mass spectrometer system as a function of electron energy E (0≤E≤180 eV) and as a function of cluster size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426962
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Dynamics of transition-metal clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 189-191 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 64.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The atomic structure and thermodynamic properties of transition-metal 6- and 7-atom clusters are investigated using the molecular dynamics method, where Gupta's potential taking into account many-body interaction is employed. The caloric and the structural fluctuations are studied. The “fluctuating state” is found forN=6 in the region of the temperature near and below the melting point, where clusters undergo structural transition from one isomer to others without making any topological change. The fluctuating state differs from the “coexistence state” found in Ar clusters [1] i.e. the former involves no liquid state. In the liquid state the motion of atom-permutation occurs besides the breathing motion. On the other hand, the fluctuating state is not found forN=7 but only the motion of atom-permutation in the liquid state. The coexistence state is found in both cases of 6- and 7-atom clusters. We also discuss a possibility of larger clusters displaying the fluctuating state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426935
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Theoretical study of the stability of X N n (n=−1, 0, +1, +2; X=Ag, Cu;N≤25) clusters as a function of size using a non-local density functional formalism (1989)
    Springer
    The European physical journal 12 (1989), S. 209-211 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The spherical jellium model and self-consistent Weighted Density Approximation (WDA) to density functional theory have been used to study the stability of X N n (n=−1, 0, +1, +2; X=Ag, Cu;N≤25) clusters. The calculated magic numbers coincide with the observed ones. The first (IP1) and second (IP2) ionization potentials of Ag N and Cu N as a function of size show the typical oscillations induced by the electronic shell-filling effect. IP1 of Cu N is about 0.5 eV higher than IP1 of Ag N in the range studied (N≤25). For both Cu N and Ag N , IP1 appears to converge well towards the respective experimental values of the work function. The use of WDA allows us to obtain bound negative clusters of small size or with a nearly empty external shell, which is not possible using the Local Density Approximation (LDA) [1, 2]. However the electron affinity of X N clusters obtained as the difference of energies of the neutral and the negatively charged clusters, becomes negative forN=2, 3 and 8 (very close to zero forN=8), revealing that WDA needs further refinements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426939
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Cluster cations ejected from liquid metal ion source: alkali metals (Li, Na) and group IV elements (Si, Ge, Sn, Pb) (1989)
    Springer
    The European physical journal 12 (1989), S. 225-227 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 79.70 ; 35.20.X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Cluster abundance of Li n + (n≤19), Na n + (n≤25), Si n z+ (n≤8 forz=1, 3≤n≤7 forz=2), Ge n z+ (n≤11 forz=1, 3≤n≤9 forz=2,n=4 forz=3), Sn n z+ (n≤7 forz=1, 3≤n≤9 forz=2,n=4 forz=3) and Pb n z+ (n≤6 forz=1, 5≤n≤7 forz=2) ejected from a liquid metal ion source has been investigated by mass spectrometry. The abundance spectra of alkali metal clusters showed distinct maxima and steps atn=3, 7, 9, 13 and 19 for Li, and atn=3, 5, 11, 13 and 19 for Na. Mass spectra of Si, Ge and Sn clusters were very similar each other, showing intensity drops aftern=4 and 6 (and alson=10 for Ge) for singly charged clusters. The magic numbers observed are discussed in terms of stability of charged clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426943
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    NMR of metal-core bonded31P in polynuclear metal cluster compounds (1989)
    Springer
    The European physical journal 12 (1989), S. 451-452 
    Details
    ISSN: 1434-6079
    Keywords: 76.60 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper we present measurements of nuclear relaxation times of31P in the polynuclear cluster compounds Au55(PPh3)12Cl6 and Ru55(P(t-Bu)3)12Cl20. Above 15 K the data can be described as a Korringa process, while below 15 K the relaxation time appears to be thermally activated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426994
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Cluster-model study of the interaction of halogen atoms with Ag clusters (1989)
    Springer
    The European physical journal 12 (1989), S. 543-546 
    Details
    ISSN: 1434-6079
    Keywords: 31.20 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Analysis of ab initio wave functions shows that the interaction between halogen atoms (F, Cl, and Br) and Ag clusters is ionic, and that the halogen ionicity is essentially −1. The interaction and the bonding arise, almost entirely, from the Coulomb attraction between the charged halogen and the metal and from polarization of the two subunits. Large shifts in equilibrium bond distances and vibrational energies are caused by an external electric field. These changes arise from a dominant Stark effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427014
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Reactions of small carbon cluster ions with HCN: a structural probe (1989)
    Springer
    The European physical journal 12 (1989), S. 567-570 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 82.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The results of a detailed study of the primary and secondary reactions of carbon cluster ions, C n + (3≤n≤20), with HCN are presented and discussed. The experiments were performed in a Fourier transform (ICR) mass spectrometer, using direct laser vaporization of graphite to form the carbon cluster ions. Evidence for two structural forms of then=7, 8 and 9 cluster ions is obtained from their differing reactivity with HCN. The C 7 + ion is anomalous in its behavior in many respects, which is interpreted by an isomerization mechanism. The HCN reactions offer a contrast to the reactions with nonpolar neutrals studied previously. All HCN reactions produced ions of the type CnX+ (primary product) or CnXY+ (secondary product) where X, Y=H, CN or HCN. Fragmentation of the original carbon cluster was not observed, while radiative association is an important reaction channel. Low-energy collision-induced dissociation studies of the product ions support the mechanism of insertion into the H-CN bond and formation of covalent bonds at the carbene site for the primary reactions. In most secondary reactions however, the HCN associates weakly with the ion, rather than binding covalently.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427019
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Internal temperatures of neutral sodium clusters: a “PIE-thermometer” (1989)
    Springer
    The European physical journal 13 (1989), S. 171-178 
    Details
    ISSN: 1434-6079
    Keywords: 35.20.V ; 35.20.W ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Distinct temperature effects could be observed in the threshold regions of photoionisation efficiency (PIE) measurements of sodium clusters. Simulations of the PIE thresholds at various temperatures were carried out with a simple, semiclassical model. Fitting the simulations to the experimental data allows to correct ionisation potential assignments for thermal effects and estimate internal temperatures of polyatomic sodium clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01398587
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Photoionisation studies of homogeneous argon and krypton clusters using TPEPICO (1989)
    Springer
    The European physical journal 14 (1989), S. 339-351 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 35.20.V ; 33.80.E
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The photoionisation threshold region of homogeneous Argon and Krypton clusters Ar n and Kr n forn up to 24 formed in a free jet expansion has been studied in detail, using the threshold photoelectron photoion coincidence (TPEPICO) time of flight technique. Measurements performed at a variety of different expansion conditions (nozzle temperature and stagnation pressure) demonstrate that fragmentation of larger clusters contributes substantially to the shape of the TPEPICO spectra even for the smallest clusters and at all photon energies higher than about 200 meV to 400 meV above the ionisation threshold. The determination of ionisation potentials for these cluster ions is discussed and careful estimates are given and compared with recent theoretical values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429284
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Multi-reference configuration interaction calculations on the systems Xe 2 + and Xe 3 + (1990)
    Springer
    The European physical journal 15 (1990), S. 161-169 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 31.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Potential curves for the ground (2Σ u + ) and the three lowest excited states of the Xe 2 + dimer ion (2Π g ,2Π u ,2Σ g + ) have been calculated using pseudopotentials in MRD-CI (multi-reference single anddouble excitationconfigurationinteraction) calculations. Spin-orbit interaction — leading to the six states 1.(1/2) u , 1.(3/2) g , 1.(3/2) u , 1.(1/2) g , 2.(1/2) u , 2.(1/2) g — has been taken into account using a semiempirical technique [1]. Subsequently, starting with a relaxed Xe 2 + ion in its ground state, the potential energy surface for the system Xe-Xe 2 + was studied. We found that the collinear approach of the Xe atom leads to the most stable geometry. This is a linear symmetric molecule with bond lengths of 6.38 bohr. In the bestT-shaped structure, the Xe atom is 7.83 bohr away from the midpoint of the Xe 2 + (r=6.1 bohr) dimer. The calculated binding energy of 0.25 eV for the equilibrium structure of the Xe 3 + molecule (i.e. the linear symmetric geometry), is in very good agreement with experimental results of 0.27 ± 0.02 eV [2].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437010
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Ab initio study of small He cluster ions He n + ,n=2, 3, 4, 5, and low-lying Rydberg states of He4 (1990)
    Springer
    The European physical journal 16 (1990), S. 219-227 
    Details
    ISSN: 1434-6079
    Keywords: 31.20.T ; 35.20.G ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract SCF and CEPA calculations are applied to study the structure of small He cluster ions, He n + ,n=2, 3, 4, 5 and some low-lying Rydberg states of He4. The effect of electron correlation upon the equilibrium structures and binding energies is discussed. He 3 + has a linear symmetric equilibrium geometry with a bond length of 2.35a 0 and a binding energyD e =0.165 eV with respect to He 2 + +He (experimentally:D 0=0.17 eV which corresponds toD e ≈0.20 eV). He 4 + is a very floppy molecular ion with several energetically very similar geometrical configurations. Our CEPA calculations yield a T-shaped form with a He 3 + centre (R e = 2.35a 0) and one inductively bound He atom (4.39a 0 from the central He atom of He 3 + ) as equilibrium structure. Its binding energy with respect to He 3 + +He is 0.031 eV. A linear symmetric configuration consisting of a He 2 + centre with a bond length of 2.10a 0 and two inductively bound He atoms (4.20a 0 from the centre of He 2 + ) is only 0.02–0.03 eV higher in energy. We expect that in larger He cluster ions structures with He 2 + and He 3 + centres andn−2 orn−3 inductively bound He atoms have nearly the same energies. In He4 a low-lying metastable Rydberg state (3 Π symmetry for linear He 4 * ,3 B 1 for the T-shaped form) exists which is slightly stronger bound with respect to He 3 * +He than the corresponding ion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437335
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Silver clusters from nozzle expansions (1990)
    Springer
    The European physical journal 17 (1990), S. 157-158 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 61.50.C
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This note reports on the first successfull experiments to generate silver clusters (N≦100) in supersonic nozzle flows. A mixture of argon/silver-vapor was used expanding from a conical nozzle (0.35 mm, 10° full cone angle, 17 mm long conical section). Source temperature and total pressure ranged up to 2200 K/300 kPa, and silver partial pressure up to 25 kPa. The data confirm the scaling laws developed to compare clustering of metals with that of rare gases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437893
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Studies of Sb and Bi cluster produced by laser desorption (1991)
    Springer
    The European physical journal 19 (1991), S. 203-206 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 79.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Direct production of cations and anions of metal clusters of Sb and Bi by laser evaporation in a vacuum has been studied. Bulk sample substrates are irradiated by 1064, 532 and 355 nm beams at variable intensity, and the ions produced are accelerated and identified by time-of-flight mass spectrometry. At 1064 nm, the cation distributions show that Sb 3 + and Bi 3 + are the most abundant species, while the monomer and dimer cations are almost non-existent. The anion spectra indicate very low yields of Sb− and Bi− with dominant dimer anion species. These patterns persist with laser power variation within the stable operation domain. With lower incident laser wavelength, the mass distributions are modified, favouring the production of the light cluster ions. In no circumstances were Sb and Bi ions withn〉5 observed. Many of the observed phenomena can be explained if one assumes that for these elements, clusters withn〈6 are formed on the substrate surface. Cluster ions are produced via a prompt desorption process, and are subjected to photon induced reactions due to the same incident laser beam. However, more detailed investigation of the desorption properties will be necessary to confirm such a desorption mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01448292
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    STM observation of Au fine-particles on graphite (1991)
    Springer
    The European physical journal 19 (1991), S. 333-335 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 61.16.D ; 82.65.F
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Gold particles deposited on graphite in vacuum have been studied by STM observation in air. Liquid-like coalescence between small gold-particles has been observed near room temperature. Preparation of small particles in vacuum is discussed. Small particles are formed in nucleation process if the degree of coalescence of particles is reduced. Over 400 Au particles of 5 nm in diameters with a narrow size-distribution with FWHM 2 nm and a high density of 3×1012/cm2 is prepared by evaporating gold in a vacuum of about 2×10−5 Torr and at the substrate (HOPG) temperature of 20°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01448323
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Adsorption — desorption kinetics on epitaxially oriented palladium clusters (1991)
    Springer
    The European physical journal 19 (1991), S. 347-351 
    Details
    ISSN: 1434-6079
    Keywords: 82.65.Jv ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Palladium clusters with a low size dispersion and a single crystallographic shape have been obtained by epitaxial growth on (100) MgO. The isothermal adsorption — desorption kinetics of CO is obtained by a molecular beam method allowing the direct determination of the global adsorption probability and of the mean life time of CO molecules on the clusters. Three main results are deduced from these measurements: — an increase of the adsorption rate of CO on the clusters by the capture of CO molecules physisorbed on the substrate, — a faster desorption rate from (100) than from (111) facets at high coverage, — an increase of the adsorption energy for clusters smaller than 3 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01448326
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Structural stability and energetics of C, Si, and Ge microclusters: empirical many-body potential energy function calculation (1991)
    Springer
    The European physical journal 19 (1991), S. 423-425 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The structural stability and energetics of carbon, silicon, and germanium microclusters containing 3−7 atoms have been investigated by using a recently developed empirical many-body potential energy function (PEF), which comprises two- and three-body atomic interactions. The PEF satisfies both bulk cohesive energy per atom and bulk stability exactly. It has been found that the most stable C3−4 microclusters are linear withD ∞h symmetry but C5−7 microclusters are planar withD nh symmetry. Silicon and germanium microclusters show similar structural stability. TheX n (X=Si, Ge;n=3−7) microclusters are found to be most stable in the following forms:X 3 is triangular withD 3h symmetry,X 4 is tetragonal withT d symmetry,X 5 is square pyramidal withD 4h symmetry,X 6 is bipyramidal square withO h symmetry, and finallyX 7 is square pyramidal having two atoms underneath withD 2h symmetry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01448343
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    C n carbon clusters (n=4−6, 60, 70): interesting cases of computation/observation comparisons (1991)
    Springer
    The European physical journal 19 (1991), S. 431-433 
    Details
    ISSN: 1434-6079
    Keywords: 35.20 ; 36.40 ; 82.30Q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recent theoretical studies proved some of the small carbon clusters C n (n≈1−10) are represented by several isomeric structures. Evaluation of the isomer relative stabilities is necessary for comparison of theoretical data with observation, this being exemplified by the C4 and C6 cases. For the former cluster a new energy estimation has been suggested based on the isomerism reasoning. Relative-stability evaluation for clusters of different dimensions is discussed on the C60/C70 system, pointing out a strong pressure-dependency of the picture. The scheme is matched to the recent observations of Bethune and Meijer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01448345
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Structural fluctuation of Au55 and Au147 clusters: Substrate effect (1992)
    Springer
    The European physical journal 24 (1992), S. 377-384 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Structural fluctuation of Au55 and Au147 clusters with and without the substrate interaction are examined using model potentials and the transition state theory. It is shown that, for Au55 both with and without the substrate interaction, the cuboctahedral structure (COCT) has a lifetime too short to be observed with an electron microscope while the icosahedral structure (IC) has a lifetime long enough. On the other hand, for Au147 without the substrate interaction, both COCT and IC have lifetimes long enough but the lifetime of IC is too long for both of them to be observed in an observation period, say in several minutes. However, the lifetime is so much reduced by the substrate interaction that both the structures can be observed in an observation period. These results are compared with the experimental facts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426687
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Stability, structures and a hypothetical growth mechanism of carbon 5/6 network (1993)
    Springer
    The European physical journal 26 (1993), S. 69-73 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A novel picture of growth of fullerene and fullerene-like structures is proposed. The ring stacking model have been studied in detail in connection with the stability, structures and growth mechanism of carbon 5-and 6-membered ring network. Combining the model with energetic considerations, the selective formation of sizes and isomers of large fullerenes has successfully been described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Physical and chemical probes of metallic clusters (1993)
    Springer
    The European physical journal 26 (1993), S. 1-7 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Two different approaches for studying the electronic structure of clusters are presented. The physical probe uses the photoexcitation of size selected alkali-atom clusters. Giant resonances govern the absorption cross-section. It is due to the collective excitation of delocalized valence electrons. The behavior of the resonance up to large sizes, 900-atom clusters for potassium and 1500-atom clusters for lithium puts into evidence the failure of the jellium model for lithium. The chemical approach makes use of the nucleation process in the presence of oxygen. From the analysis of mass spectra of oxidized products, informations are gained on the valence of metallic atom in the cluster oxide. The method is applied to europium and thulium clusters. A comparison is done with the simple case of alkali clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429095
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Excitation and radiative decay of neutral and ionic ArN clusters studied by fluorescence spectroscopy (1993)
    Springer
    The European physical journal 26 (1993), S. 370-372 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 78.55-M
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Excitation and decay processes of neutral and ionized ArN clusters are analysed using fluorescence spectroscopy with synchrotron radiation. The fluorescence yield of ionized ArN clusters is resonantly enhanced after excitation from states related to the atomic 3s levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01429198
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    On the shell structure and geometry of monovalent metal clusters (1991)
    Springer
    The European physical journal 21 (1991), S. 271-279 
    Details
    ISSN: 1434-6079
    Keywords: 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Hückel model is used to study the electronic structure of monovalent metal clusters. In an fcc cluster the Hückel model gives an estimate to the electronic structure of a free electron cluster. It is shown that the surface faceting of the fcc cluster can destroy the electronic shell structure already when the cluster has about 100 electrons. In the Hückel model the icosahedral structure has smaller total energy than the fcc structures, from which the Wulff construction has the smallest energy already when the cluster has 600 atoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426385
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    The structure of deposited metal clusters generated by laser evaporation (1991)
    Springer
    The European physical journal 21 (1991), S. 285-288 
    Details
    ISSN: 1434-6079
    Keywords: 36.40 ; 35.20
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Metal clusters have been produced using a laser evaporation source. A Nd-YAG laser beam focused onto a solid silver rod was used to evaporate the material, which was then cooled to form clusters with the help of a pulsed high pressure He beam. TOF mass spectra of these clusters reveal a strong occurrence of small and medium sized clusters (n〈100). Clusters were also deposited onto grid supported thin layers of carbon-films which were investigated by transmission electron microscopy. Very high resolution pictures of these grids were used to analyze the size distribution and the structure of the deposited clusters. The diffraction pattern caused by crystalline structure of the clusters reveals 3-and 5-fold symmetries as well asfcc bulk structure. This can be explained in terms of icosahedron and cuboctahedron type clusters deposited on the surface of the carbon layer. There is strong evidence that part of these cluster geometries had already been formed before the depostion process. The non-linear dependence of the cluster size and the cluster density on the generating conditions is discussed. Therefore the samples were observed in HREM in the stable DEEKO 100 microscope of the Fritz-Haber-Institut operating at 100 KV with the spherical aberrationc S =0.5 mm. The quality of the pictures was improved by using the conditions of minimum phase contrast hollow cone illumination. This procedure led to a minimum of phase contrast artefacts. Among the well-crystallized particles were a great amount of five- and three-fold symmetries, icosahedra and cuboctahedra respectively. The largest clusters with five- and three-fold symmetries have been found with diameters of 7 nm; the smallest particles displaying the same undistorted symmetries were of about 2 mm. Even smaller ones with strong distortions could be observed although their classification is difficult. The quality of the images was improved by applying Fourier filtering techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426387
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...