ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 36.40.+d  (123)
  • Springer  (123)
  • Oxford University Press
  • 2020-2022
  • 1990-1994  (123)
  • 1993  (123)
Collection
Publisher
  • Springer  (123)
  • Oxford University Press
Years
  • 2020-2022
  • 1990-1994  (123)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 56 (1993), S. 215-217 
    ISSN: 1432-0630
    Keywords: 71.25.Mg ; 71.25.Rk ; 71.20.−b ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A tight-binding method which has been previously applied to study the effect of uncorrelated orientational disorder on conduction-band properties is extended here to the case of systems with long-range order and/or short-range correlations. The density of states and conductivity are not highly sensitive to the specific short-range correlations, so long as the system is not too close to being fully ordered. Hence the strong effects of disorder found previously appear to be robust and should play an important role in the interpretation of normal-state properties of A3C60.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 57 (1993), S. 101-104 
    ISSN: 1432-0630
    Keywords: 73.20.Mf ; 82.65.Pa ; 82.50.−m ; 36.40.+d
    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 from the surface of small metal particles has been investigated as a function of the shape of the particles and the polarization of the incident laser light. The particles were supported on LiF, quartz or sapphire substrates. In a first set of experiments, the shape of the particles was determined by recording optical transmission spectra with s- and p-polarized light incident under an angle of typically 40° with respect to the surface normal. The metal particles turn out to be oblate, the ratio of the axes perpendicular and parallel to the substrate surface being on the order of 0.5. This ratio decreases with increasing particle size. Also, the particles change shape if the temperature is raised. In further experiments, s- and p-polarized light has been used to stimulate desorption of atoms via surface plasmon excitation. It is found that the desorption rate markedly depends on the polarization of the light. This is explained by excitation of the collective electron oscillation along different axes of the non-spherical particles.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1434-6036
    Keywords: 36.40.+d ; 74.75.+t ; 79.60.−i
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The electronic structure of K-doped C60 was investigated by photoemission (PE) and X-ray absorption near-edge structure (XANES) studies at the C-1s and K-2p thresholds. In addition, information on the local K-derived partial density of states in superconducting K3C60 was obtained by resonant PE at the K-2p 1/2 threshold. The experimental observations support a complete charge transfer from K to C60 and we clearly observe a finite density of states atE F . From resonant PE, occupied states with K-p, d character could be identified in the binding-energy region from 1.5 to 8 eV below, but not directly at the Fermi level. This partial-density-of-states structure agrees well with the results of our band-structure calculations based on the local-density approximation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 141-143 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 61.50.Lt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Size selected silicon clusters have been isolated in rare gas matrices and studied by optical absorption spectroscopy. The clusters were produced in a pulsed laser vaporization source, size selected with a quadrupole mass spectrometer and deposited at low energies into a cocondensed krypton matrix held at T〈20 K. A comparison of the optical spectra of ten atom wide bands (Si25-Si35, Si35-Si45 and Si45-Si55) shows the general size evolution of the optical properties. Single cluster sizes have also been isolated and show somewhat sharper spectra than the bands. The measured spectra show similarities to spectra calculated using Mie theory and bulk optical constants. Cluster-cluster agglomeration was studied by evaporating the inert gas matrix. The results suggest that the clusters agglomerate into larger particles even under the mildest "soft landing" conditions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 159-161 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 82.30.N ; 82.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new class of molecular clusters with the composition M8C12 (M=Ti, V, Hf and Zr) has been discovered. The cation, anion and neutral species are unusually abundant and stable. In the case of the Zr-C system, evidence has also been obtained for growth through the development of multicage structures.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 195-197 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 05.45.+b
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The structure and long-time dynamics of (LiBr) n n=4,5,8 were studied by optimization and molecular dynamics. The ring structure, double ring stack for (LiBr)8, was found to be the energy minimum. They are dynamically flexible and, particularly for (LiBr)4 and (LiBr)5, hardly isomerise into other isomers determined by optimization. (LiBr)8 is probably a promising candidate to exhibit dynamic coexistence among a number of isomers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 207-209 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.20. Ea ; 33.80 Gj
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report the vibrational spectra of the cluster ions Cs+(CH3NH2)N, N=3–22. Bands in the 1015–1050 cm−1 region of the infrared are due to the v8 mode (CN stretch) of methylamine molecules displaying different degrees of interaction with the central ion. Monte Carlo simulations of the solvated Cs+ ion indicate that nine methylamine molecules fill the first solvation shell of Cs+ and that possible rearrangements in cluster structure occur at N=14−15. No absorptions due to bulklike methylamine molecules are observed through N=22.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 217-219 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.70.Jg ; 34.10.+x
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present results of semiclassical simulations of the electronic spectra and dynamics of aniline-Arn (1≤n≤3) clusters. The spectral density formalism of Mukamel [3] is used to generate the spectra from the time dependent energy difference of the S0 and S1 states of aniline solvated by the argon atoms. A repulsive Ar-N interaction is incorporated in the Hamiltonian of the S1 state; this term permits a quantitative prediction of the origin shifts of the S1〈--S0 transition (both red and blue shifts) for all the clusters studied. The temperature dependence of the spectrum of aniline-Ar2 is correlated with the underlying dynamics of this cluster.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 33-35 
    ISSN: 1434-6079
    Keywords: 33.80.-b ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using picosecond pump&probe technique followed by mass-selective detection, the dynamics of excited states of cold Nan=3...8-clusters in a supersonic beam — excited at λ=422nm — have been studied in time-resolved two-photon-ionization (TPI)-experiments. With growing cluster size a monotonous decrease of the decay times is observed except in the case of Na7 known to be a very symmetric cluster.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 166-168 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 61.22.Pg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe here molecular dynamics computer simulations performed to study the solvation of ions (Cl− and Na+) in water clusters. Our simulations show that the calculated structure and dynamics of the clusters is very sensitive to the potential model which is used to describe the interactions. From the comparison with thermodynamic data and data from the photoelectron spectra we conclude that in Cl−(H2O)n (n≤20) clusters the ion is located on the surface of the cluster.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    ISSN: 1434-6079
    Keywords: 31.10.+z ; 36.40.+d ; 33.45.+x ; 33.60.-q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We discuss the electronic structure, bonding and physical properties of the gold cluster compound Au55(PPh3)12Cl6. Results from our experimental measurements, including EXAFS, specific heat, Mössbauer, UV-visible and photoelectron spectroscopy, are combined with those of other work to form a consistent physical picture of the system. The bonding in Au55(PPh3)12Cl6 is much more delocalised and non-directional than in smaller gold cluster molecules. The Au55 cluster exhibits a substantial degree of metallic bonding, while displaying some of the characteristics of a discrete energy level spectrum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 178-180 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The (KCl)32 cluster is used as a model system to study the possibilities for clusters to exhibit amorphous or glassy solid forms. The problem has two aspects: first, whether the potential surface of the cluster supports a myriad of locally stable, disordered structures, the ensemble of which would constitute the glassy state, and second, whether an ensemble of amorphous clusters can be prepared under laboratory conditions. Molecular dynamics studies give an emphaticyes to the first issue, and an equally emphaticno to the second, for cooling rates up to 1012 K/s, a thousand-fold faster than the fastest rates yet reported. However, if the long-range Coulomb interaction of the ions is replaced by a shielded Coulomb (Debye or Yukawa) potential, the secondary minima are sufficiently stabilized and the saddles, sufficiently high, that disordered equilibrium structures can be reached by cooling at fast, but still conceivably attainable rates. The implication is that while alkali halide clusters probably cannot form glasses, binary clusters with shorter-range forces, such as those of II–VI and III–V compounds, probably can form glasses. The highly disordered structures of (KCl)32 are perhaps the most disordered forms yet seen for solid matter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 192-194 
    ISSN: 1434-6079
    Keywords: 31.20.Tz ; 31.50.+w ; 33.10.-u ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Stable ground state structures for neutral and charged Li n H, Li n H2 and Na n F m (n↛m) have been determined usingab —initio methods accounting for electronic correlation effects. The consequences of replacing alkali-atom by foreign-atom or -atoms have been studied. The similarities and differences with respect to topologies of the most stable Li n and Na n clusters will be pointed out. The ionization potentials and spectroscopic patterns are compared with available experimental data. This allows for the geometrical and spectroscopic assignments as well as for a study of the influence of localized versus non localized bonding on the ground and excited state properties of mixed clusters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 270-272 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.20.Kf ; 35.20.Pa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The B state of Na3 is often cited as an example of fractional quantization of the pseudorotational motion on the lower adiabatic surface of theE×e Jahn-Teller system. Recently, an alternative interpretation of the experimental results was given which is based on a pseudo-Jahn-Teller treatment and implies integer quantization. We present rotationally resolved spectra of a number of vibronic bands of the Na3 B-X system and believe that they can only be explained in terms of integer quantum numbersj of the vibronic angular momentum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 301-303 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 75.50.Cc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We use a variation of the Stern-Gerlach experiment to study the magnetic behavior of transition metal clusters. We report measurements of the magnetic properties of nickel clusters as a function of cluster size, vibrational temperature, and applied magnetic field. Results for these nickel clusters resemble those previously published for cobalt clusters in that superparamagnetic behavior is observed. As is the case for cobalt clusters, nickel clusters are observed to have magnetic moments per atom that are greater than the bulk value.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 325-327 
    ISSN: 1434-6079
    Keywords: numbers 75.50Bb ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Magnetic properties of small iron clusters in a supersonic molecular beam are investigated. The magnetization is probed as function of magnetic field, temperature and cluster size. Temperatures are controlled by changing the source temperature (100 K to 500 K) and the expansion conditions. The clusters also may be heated in flight with light from a pulsed laser. Hot clusters are found to be superparamagnetic however cold clusters are not but show strongly reduced magnetization which furthermore is non-linear with the applied field. Experimentally it is found that the anomalies are related to the cluster rotations. We also address a controversy between our earlier findings [1] and those by Bucher et al. [2], and demonstrate that their temperature determinations and consequent conclusions are incorrect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 352-354 
    ISSN: 1434-6079
    Keywords: .64.70.Fx ; 36.40.+d ; 35.20.Vf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper, we report properties of selenium clusters produced by vapor condensation technique. Impact electronic ionization is performed on clusters in the size range from 2 to 36 atoms. The measured ionization potentials exhibit small oscillation corresponding to the wiggles observed on the mass distribution. An attempt to connect these experimental observations with the geometrical structure of the molecules is made in the discussion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 394-396 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Noble gas atoms trapped in the intracrystalline cavities of zeolites may form clusters. A classical-mechanical isoenergetic molecular dynamics simulation is performed to simulate the dynamical behavior of noble gas clusters in zeolite cavities. To implement the simulation, a model is adopted of a homogeneous spherical cavity with Morse interaction between the noble gas atoms and cavity walls. The results for Ar6 clusters indicate that the noble gas clusters in the cavity undergo the same solid/liquid phase changes as in free space, and, at high enough energies, a rapid exchange between atoms adsorbed on the inner surface and thosein the interior of the cavity. Mathematical quenching is used to investigated the multidimensional potential surface of Ar clusters in the cavity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 391-393 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 05.45.+b
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have computed the local Kolmogorov entropy of molecular dynamics trajectory segments near the potential energy saddles of model Ar3 and Ar5 clusters. In the case of Ar3 clusters bound with a Lennard-Jones potential, the local Kolmogorov entropy of the cluster is significantly smaller in the saddle region than in other areas of the potential surface. This behavior indicates an increase in the degree of nearly quasiperiodic motion near the Ar3 saddle due to the partial decoupling of the cluster's vibrational modes there. Lennard-Jones Ar5 clusters do not exhibit similar behavior, but Ar5 clusters bound with a short-range Morse potential do. This suggests that the “regularizing” effect of saddle regions is strongly dependent on the shape of the energy surface near the saddle. From these observations, we can determine which features of the saddle are most important in this respect; the flatness of the saddle region seems to be one such feature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 95-97 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.20.Kf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The dipole surface plasmon forK N + clusters is analyzed using the RPA sum-rule technique within a semiclassical Density Functional Theory and the spherical jellium model. The theoretical frequencies are blue shifted as compared to the experimental ones. The discrepancies between theory and experiment are reduced when considering non-local energy contributions in the density functional and phenomenologically including atomic lattice effects by means of an electron effective mass and a static dielectric constant.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 73-75 
    ISSN: 1434-6079
    Keywords: 61.14.−x ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Calculations of the dynamical Debye-Scherrer electron diffraction pattern for ultrafine gold and silver particles have been performed using the multislice method. Two cluster sizes, 31 and 55 Å in diameter (923 and 5083 atoms, respectively), of both f.c.c. and icosahedral structures were used, at incident voltages of 40 kV and 100 kV.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 92-94 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 03.65.Sq ; 33.80.Eh ; 35.20.Vf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Neutral aluminum clusters have been produced by laser vaporization technique, ionized by a low-power near-threshold laser light and detected using standard TOF spectrometric methods. Ionization potentials have been deduced in the low size range. In the large size range 250〈N〈1400 the patterns of the mass spectra exhibit a regular and continuous oscillation, originating from size-dependent ionization threshold effects. The period, constant on a Ne 1/3 scale (Ne=3N is the number of valence electrons), is approximately two times shorter than the one observed in alkali experiments. This feature is analyzed in terms of shell structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 110-112 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 21.60.Cs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Under experimental conditions which do not favor delocalization of valence electrons alkali atoms remain neutral and are taken as atomic fermions. Thus, two neutral alkali component microclusters are treated by a two-fermion shell model producing two sets of magic numbers containing many common numbers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 113-114 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 82.80.Ms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The present paper supports coexistence of electronic shells and shells of ion cores for large alkali clusters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 146-149 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.60.Cv ; 07.77.+p
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Bismuth cluster anions are produced in a new type of source (PACIS). For Bismuth the intensity is estimated to be 10 times higher than that of a laser vaporization source. UV-photoelectron spectroscopy serves to study the electronic level structure of the cluster anions. In the photoelectron spectra of Bi 2 − , Bi 3 − and Bi 4 − the main transitions agree with earlier results of LIF investigations on the neutral species as well as with recent theoretical and experimental data. Here we present a first extension to higher photon energies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 15-17 
    ISSN: 1434-6079
    Keywords: 68.35.Bs ; 36.40.+d ; 35.20.Bm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Rigorous analytical formulae for mean nearest-neighbour coordination numbers in clusters as a function of cluster size have been derived for a range of geometries: the tetrahedron, octahedron, cuboctahedron, icosahedron and bcc rhombic dodecahedron. Formulae for outer-neighbour coordination numbers are also reported, including a complete analysis of interatomic distances and mean coordination numbers in icosahedra. The formulae will find application in studies of electronic structure and interpretation of EXAFS data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 180-182 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.80.Eh
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Electronically excited states of magnesium-water cluster ions, Mg+(H2O) n ,n=1–5, are studied by photodissociation after mass selection. The observed photodissociation spectra are assigned to the2P–2S type transitions localized on the Mg+ ion with the aid of ab initio CI calculations. In addition to evaporation of water molecules, photoinduced intracluster reaction to produce MgOH+(H2O) n is found to occur efficiently, with pronounced size dependence. The intriguing features observed in the mass spectrum of nascent cluster ions are discussed in relation to the stepwise solvation of this reaction.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 213-215 
    ISSN: 1434-6079
    Keywords: 31.20.Di ; 31.20.Gm ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper we present the theoretical results obtained for (NaCl) n clusters withn≤19. The calculations were performed using the ab-initio Perturbed-Ion (PI) model. That model was first developed for the study of ionic crystals and we have adapted it to study clusters. Within the PI method we can determine the total energy of the cluster as a function of the position of the atoms in the cluster and minimizing the total energy with respect to the positions of the atoms we can obtain the ground state geometry and other related properties. The results obtained for the equilibrium geometries are in good agreement with theoretical calculations using pair potentials. The study of the relative stabilities of clusters with different numbers of molecules show that the clusters are specially stable for n=4, 6, 9, 12, 15, 16 and 18 molecules, in good agreement with experimetal results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 237-239 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.20.Ej ; 31.20.Tz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In this paper, we report the results ofab initio molecular orbital calculations on cube-like (MgO)n clusters (n=1−13). We determine the relative stability of the clusters by analyzing binding energies and dissociation energies involved in the evaporation of a neutral MgO monomer. The calculated magic numbers are in very good agreement with the abundance maxima observed in the mass spectra. We also explore the size-dependence of structural, energetic and electronic properties of the clusters, finding different rates to reach the corresponding bulk limit.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 255-257 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.90.+s ; 71.45.Nt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A local-density approximation calculation is performed on various M8C12 structures, including Ti8C12, V8C12, VTi7C12 and ScTi7C12. It is found that the magic numbers observed during the experimental discovery of these species does not depend on the details of the electronic structure, but rather can be described as a chemical system derived from ethylene.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 282-284 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 71.45.−d ; 78.65.−s
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We discuss the collective dipolar resonances of theC 60 molecule described by a spherically symmetric shell. The shell is modeled by a step in the radial direction. We present results for π and π+σ plasmons in good quantitative agreement with recent experiments. New features, like a monopole mode of oscillation, are predicted for theC 60 molecule.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 300-304 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 34.50.-s
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This article reviews recent work in Los Angeles on elementary processes in fullerene vapors. The production of fullerene molecules typically involves extreme high-temperature conditions and processes which are poorly understood at date [1–3]. Once generated, these molecules may represent the most stable molecules known [4,5]. In a recent work [C. Yeretzian et al., Nature 359, 44 (1992)] we presented clear evidence for coalescence reactions between fullerene molecules. Mass spectrometric measurements on hot, dense vapors of small fullerenes (C60 and C70) reveal the formation of stable higher fullerenes which are multiples of the initial masses. These processes are shown to occur in the gas-phase rather than in the solid film and their dependences on laser fluence and He-gas pressure are investigated. Three distinct reactions are proposed—coalescence, emission and capture—to account for the observed distributions at higher fullerene sizes. Specifically, the heat of coalescence is released through emission of small, even-numbered fragments which, in a very dense vapor, are efficiently captured by other coalesced fullerenes. These findings have implications for the long-time stability of the fullerene vapor, and for the mechanism of fullerene formation and growth, and may open new ways to the synthesis of selected higher fullerenes and encapsulation compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    ISSN: 1434-6079
    Keywords: 07.77.+p ; 34 ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The hydrogen cluster accelerator existing at Institut de Physique Nucléaire de Lyon (IPN Lyon) has been upgraded by adding a Variable Energy Post-accelerator of RFQ type (VE-RFQ). This operation has been performed in the frame of a collaboration between KfK Karlsruhe, IAP Frankfurt and IPN Lyon. The facility has been designed to deliver beams of mass selected Hn+ clusters, n chosen between 3 and 49, in the energy range 65–100 keV/u. For the first time, hydrogen clusters have been accelerated at energies as high as 2 MeV. This facility opens new fields for experiments which will greatly benefit from a velocity range never available until now for such exotic projectiles.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 28 (1993), S. 67-72 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 71.28.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Rare earth clusters of europium, thullium and ytterbium were generated by gas aggregation technique and probed by photoionization mass spectrometry. Their relative intensities in mass spectra have shown that their stabilities are governed by compact geometrical structures. The addition of oxygen gas in the nucleation region was used to produce the reactive nucleation. Several stages of oxidation were observed as a function of oxygen pressure up to saturation. For the maximal degree of oxidation the observed oxide ion compositions enable one to follow the valence of metal atom in its oxide as cluster size increases. This exhibits a divalent to trivalent valence change with cluster size. Moreover it emerges from the data that the divalent to trivalent transition for Tm, Yb, and Eu occurs at different size values.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 25 (1993), S. 261-265 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 79.20.Kz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Gold clusters with diameters from 2 to 10 nm are prepared by evaporation on mica substrates. They are investigated with low energy electron loss spectroscopy in the reflected beam and characterised in a transmission electron microscope. The energy loss spectra show a broadening of the plasma peak with decreasing particle size. The plasma frequency shifts to higher energies. The size dependence of the half width and of the plasma frequency is compared to known models. The results support the quantum box model of Genzel et al.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The optical absorption spectra of small niobium clusters have been determined over the wavelength range 260 – 740 nm by photodetaching Krypton atoms from the corresponding neutral van der Waals, vdW, complexes, NbnKrm, n=5–15, m=1–3. Cross sections for small gold clusters were determined by photodetachment experiments oncharged vdW complexes [AunXem]+, m=1, 2. The absorption cross sections are observed to increase monotonically with decreasing wavelength. At the long wavelength end of the range, the cross section is practically independent of the cluster nuclearity, n; whereas, at the short wavelength end of the range, the cross section increases monotonically with n.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 56-58 
    ISSN: 1434-6079
    Keywords: 68.35.Md ; 36.40.+d ; 64.60.-i ; 62.50.+p
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High pressure optical absorption spectra are presented for CdSe nanocrystals as a function of size. The spectra show a transition to a high pressure Rock Salt type phase at pressure greatly elevated from the bulk. The size dependence of the transition pressure can be explained in part by an increased surface tension in the Rock Salt phase relative to the low pressure tetrahedral phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 51-55 
    ISSN: 1434-6079
    Keywords: 71.10.+x ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a simulation method to determine from first principles the structure of low symmetry atomic systems. Our method is based on Langevin molecular dynamics and quantum mechanical interactions derived fromab initio pseudopotential calculations. The molecular dynamics time step with this approach can be one to two orders of magnitude larger than in the Car-Parrinello method, compensating for the time required for self-consistency at each step. Moreover, because the simulation is constrained to reside on the Born-Oppenheimer surface, this method can be used for insulating as well as metallic and charged systems. Application will be made to small silicon clusters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 105-109 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This invited review attempts to draw together recent advances in the structural characterisation of clusters and our theoretical understanding of dynamics, especially coexistence phenomena. It is now possible to characterise the potential energy surface of a small cluster in great detail, both in terms of local minima and transition states. A selection of results is collected includingab initio calculations on main group ligated clusters and a wide variety of systems bound by model analytic potentials. Useful comparisons may be made between the rearrangement mechanisms supported by the various potential energy surfaces. Furthermore, knowledge of transition states enables us to explain the results of dynamical simulations in great detail, and make comparisons with thermodynamic models. For larger systems, however, the number of stationary points is daunting, yet progress is still possible in terms of the underlying potential energy surface using the harmonic superposition approximation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 131-134 
    ISSN: 1434-6079
    Keywords: 33.80.-b ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The real-time dynamics of Nan (n=3–21) cluster multiphoton ionization and fragmentation has been studied in beam experiments applying femtosecond pump-probe techniques in combination with ion and electron spectroscopy. Three dimensional wave packet motions in the trimer Na3 ground state X and excited state B have been observed. We report the first study of cluster properties (energy, bandwidth and lifetime of intermediate resonancesNa n * ) with femtosecond laser pulses. The observation of four absorption resonances for the cluster Na8 with different energy widths and different decay patterns is more difficult to interpret by surface plasmon like resonances than by molecular structure and dynamics. Time-resolved fragmentation of cluster ions Na n + indicates that direct photo-induced fragmentation processes are more important at short times than the statistical unimolecular decay.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 204-206 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 81.10.Bk ; 35.20.Wg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using a CO2 laser we have desorbed LiOH and NaOH from a solid target into an expanding inert gas jet pulse. Subsequently the beam was ionized by photons from a UV laser. Surprisingly, we observed in mass spectra metal water clusters and metal-hydride water clusters. For the metals M=Li, Na we find that the [M(H2O)n]+ peaks are dominant for small clusters, while for large clusters (n〉20) the [MH(H2O)n]+ peaks are dominant. This indicates that the clathrate (H2O)20 may play an important role in the formation of metallo-water clusters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 226-228 
    ISSN: 1434-6079
    Keywords: 79.20.Rf ; 34.50.Lf ; 79.20.Nc ; 81.60.Cp ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We review the processes which have been observed from collisions between alkali-halide clusters and solid surfaces. Soft impact of nanocrystalline NanF n−1 + clusters against solid surfaces causes them to cleave along the lowest energy (100) plane. At higher collision energies (Ei〉1 eV/atom), an evaporative cascade occurs which is characteristic of a transformation of the nanocrystal to a molten state. Efficient F− transfer from the cluster to the surface can occur for the larger clusters (〉60 atoms) scattering from Si(111), in direct competition with the cleaving channel at low energies. In this regime, strong bonds can form between the F− and silicon surface. The reaction probability increases with cluster size indicating that an impact-initiated shock wave is needed to enhance the reactive process.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 264-266 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.90.+s
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have investigated symmetrical and asymmetrical fissions of positively charged silver clusters by a shell correction method. Contour plots of the total electronic energy as a function of deformation parameters have been obtained. They show complicated topographies arising from the shell correction.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    ISSN: 1434-6079
    Keywords: 32.80.Fb ; 36.40.+d ; 33.20.Kf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photo-absorption cross-sections for charged sodium clusters (14 to 48 atoms) have been measured for photon energies from 2.0 eV to 3.5 eV. The spectra are dominated by surface plasma oscillations of the valence electrons exhausting 70–100% of the dipole sum rule. The mean resonance energy of ≃2.75 eV is nearly independent of cluster size. A splitting of the resonance peaks is observed for non-“magic” clusters and discussed in terms of a deformation picture involving prolate and oblate shapes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 284-286 
    ISSN: 1434-6079
    Keywords: 73.20.Mf ; 36.40.+d ; 31.20.Sy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study the origin of the discrepancy between the photoabsorption cross sections of small jellium spheres calculated by the time dependent local density approximation (TDLDA) and experiments for small metallic clusters. We have specifically studied Na 21 + . We conclude that both non-local exchange-correlation effects beyond the LDA and geometrical effects beyond the jellium approximation should be taken in the same calculation. We also present local and non-local calculations for Na n − (n=19, 91 and 197) within the framework of the jellium model. The large anions show a fragmentation of the plasmon due to its interference with the ionization threshold. This feature is absent in the TDLDA results.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 296-300 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 71.10.+x
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Energetics and structures of small aluminum-lithium clusters were investigated using structure-minimization and dynamic simulated annealing on the Born-Oppenheimer surface, calculated via local-spin-density functional method. A transition from atomic-based characteristics forn≤5 to a perturbed delocalized electronic cluster-shell behavior forn≥6, containing an AiLi5 “core”, is suggested.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    ISSN: 1434-6079
    Keywords: 31.20.Tz ; 31.50.+w ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ground state geometries of small neutral Ag n (n=2–9) and charged Ag n ± (n=2–9) clusters have been determined in the framework of the SCF procedure employing a relativistic pseudopotential accounting for core-valence correlation effects (RECP-CVC). Similarities and differences between neutral and charged clusters have been found. Large scale CI for 5s electrons only has been carried out for determining stabilities, ionization potentials (IP) and vertical detachment energies (VDE) of anions. A comparison between predicted and measured observables allows for the tentative structural assignments. In addition, the low lying energies of excited states for the neutral species at the anionic geometries have been calculated to account fully for geometrical and spectroscopic assignment to the photodetachment measurements.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 8-12 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The change of the cohesive energy and the optical absorption spectra of small singly sized Hg clusters is discussed. The cohesive energy allows one to determine the different regimes of chemical bonding. The optical spectra show an abrupt transition to a collective, plasmon-like absorption as a function of increasing cluster size. The position of the one plasmon peak is: 1) independent of the charge state, 2) nearly independent of cluster size, and 3) agrees with that of the classical Mie plasmon calculated from the experimental dielectric constants. The width of the plasmon peaks is discussed. A strong influence of electronic correlations on the cluster size dependence of the oscillator strength is observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 17-22 
    ISSN: 1434-6079
    Keywords: 31.20.Tz ; 31.50.+w ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The contribution of quantum chemicalab — initio studies of optical response in small metal clusters towards understanding of their specific electronic and structural properties has been presented. The role of cluster size, geometry, number of valence electrons and chemical composition has been pointed out. It has been shown that an appropriate many-electron description of excited states for stable cluster structures allows for the quantum molecular interpretation of the absorption spectra and other optical probles. The nature of excitations responsible for characteristic spectroscopic patterns has been discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 373-376 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The paper presents an analytic model which is based on approximation of the catchment basins in cluster potential energy surface by structures of ash-tray type. In order to see how the quantities to be specified relate to those obtained by means of numerical computation, predictions for the Ar13 caloric curve are made and they are compared with computer simulation data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 65.40.−f ; 76.80.+y
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract There are 5 different Au-sites in the Au55 core of Au55(PPh3)12Cl6. The 13 inner atoms are almost identical to that of bulk gold. At the surface the attachment of the ligands is responsible for further differentiation. We have calculated the low temperature specific heat using the Mössbauer determined electrical quadrupolar splitting of the surface atoms. Due to too long a quadrupolar relaxation time, no such contribution is seen in the zero field results (down to 0.06 K) of Goll et al., Z. Phys. D 20, 329 (1991). The latter zero and in-field data are interpreted as the contribution of an electronic spin, hyperfine coupled to a nuclear spin 3/2. The effective abundance is about one spin per ten clusters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 131-133 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.20.Sy ; 03.65.Sq
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Starting from the Hartree-Fock exchange energy density of a spin saturated system and using the Density Matrix Expansion we have built a non local Energy Density Functional without problems of divergence in the large gradient limit. We have applied this functional to the study of ground state properties and the dipole excitation energies of some metallic clusters in the quantal and semiclassical approaches.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 143-145 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.20.Sy ; 71.30.+h
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Electronic structures of mercury clusters are studied by the self-consistent calculations. It is found that an icosahedral Hg13 cluster is characterized by the atomic nature with closed electronic shell configuration while a significant amount of thespd-hybridization is observed for a Hg19 cluster with a double-icosahedral shape. The electronic structure of a Hg12Ag cluster is also studied with a special focus on the electronic shell structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 137-139 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 35.20.Vf ; 33.80.Eh
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Laser photoionization experiments have been performed on a large size range of indium and thallium clusters. The metal clusters were produced by laser vaporization technique and analyzed after laser ionization by standard time-of-flight mass spectrometry. For the indium clusters, individual ionization potentials (IP) are deduced for N≤132. Abrupt decreases in the IP values are observed, which correspond to the openings of new electronic shell as predicted by the spherical jellium model. For larger indium clusters, the unresolved mass spectra present small but reproducible oscillations. Interpretations in terms of either electronic shell structure or cluster geometry remain undecided for the moment. Our results on thallium clusters are less abundant and only qualitative. Nevertheless, they show that thallium behaves more like a monovalent element than like a trivalent one.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 288-290 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.80.Eh ; 35.20.Wg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the time dependence of carbon cluster ions, formed via thermionic emission from photoexcited fullerenes (C60 and C70). By pulsing the extraction field, we are able to observe delayed ions formed as late as 100 µs after excitation at 532 nm, 355 nm, or 266 nm. All even-sized clusters in the range 36 ≤ n ≤ 70 undergo thermionic emission.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 297-299 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.60.Cv
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The electronic structure of an isolated Ca@C60 molecule was probed by photoelectron spectroscopy (PES) of Ca@C 60 − , generated by laser desorption of a preformed Ca@C60/fullerene thin film. The PES spectrum of Ca@C60 was found to be similar to that of C 60 − , except that Ca@C60 has an electron affinity of 3.0 eV, about 0.3 eV higher than that of C60. The spectrum suggests that Ca atom donates its two 4s electrons to the C60 t lu lowest unoccupied molecular orbital. Thus, the interaction between the central Ca atom and C60 is quite ionic, and Ca@C60 can essentially be expressed as Ca2+@C 60 2− .
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 311-313 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 35.20.Wg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Using a pulsed CO2 laser we have desorbed C60 clusters from a solid target into an expanding He jet, coupled to a time-of-flight mass spectrometer. We observed self ionization of the excited clusters with a time delay of 120 ±20 µs. This is large compared to previously reported delays of up to 15 µs after laser excitation with visible or ultraviolet light. We suggest that the delayed ionization is caused by structural isomers of hot C60 clusters differing from the truncated-icosahedron structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 174-176 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Cluster beams of high intensity as resulting from condensation in adiabatic nozzle expansions of pure gases or vapors can be used either for thin film deposition or for substrate erosion, depending on the cluster impact energy. For deposition, high-intensity cluster beams of zinc and of silver have been obtained for the first time from pure metal vapor nozzle expansions. The clusters contain several thousand atoms of zinc, or several hundred atoms of silver, respectively. Reflecting thin films have been deposited without ionizing and accelerating the cluster beams. For purposes of erosion, ionized clusters have to be accelerated to impact speeds larger than about 10 km/s in order to get surface erosion via shock wave induced crater formation. Crater dimensions of some nanometers are estimated, providing a limit for the spatial resolution of cluster impact lithography (CIL).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 177-179 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.80.Eh ; 33.20.Lg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Clusters of aluminum atoms solvated with water molecules, Al(H2O) n , have been studied by one-photon ionization and time-of-flight mass spectroscopy. Characteristic feature is observed in the photoionization mass spectrum: The intensities of the product Al+(H2O) n ions are about one order of magnitude larger forn≤4 than forn≥5. The ionization potentials are determined forn up to 4. The obtained results are discussed in connection with the recent theoretical works. The photodissociation spectroscopy has also been applied to the Al+(H2O) n ions withn=1−10. The observed spectra are ascribed to the transition localized on the Al+ ion on the analogy of the results of Mg+(H2O) n photodissociation. The dissociation dynamics is also discussed from the fragmentation pattern with the aid of the recent theoretical work on the structure and stability of these ions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 264-266 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.10.−n ; 34.20.cf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present the results of a first-principles calculation for the geometrical and electronic structure of C78 and C84 fullerene isomers. Our study confirms that for C84 two isomers withD 2 andD 2d symmetries are the most energetically favorable, and for C78 aC 2v isomer is the ground-state configuration. Results from the present calculation are compared with recent experimental observations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 8-11 
    ISSN: 1434-6079
    Keywords: 61.10.Lx ; 61.60.+m ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Gold L3-edge EXAFS measurements at 80 K on Au55(PPh3)12Cl6 confirm that the Au-Au distances in this amorphous metal cluster compound are significantly shorter than in bulk gold. The nearest-neighbour Au-Au distances are all equal within experimental uncertainty. Outer-shell Au-Au distances have also been resolved. The results are consistent with the cuboctahedral structure originally proposed for this cluster, but not the polyicosahedral one recently suggested. Very similar results have been obtained from the sulphonated water-soluble derivative Au55(PPh2C6H4SO3Na)12Cl6. In contrast, EXAFS of Au11{PPh2(p-ClC6H4)}7I3 has clearly resolved the two nearest-neighbour Au-Au distances associated with its icosahedral structure. Palladium K-edge EXAFS has been used to study the cluster Pd561(phen)36O200. The Pd-Pd distance is nearly equal to that in bulk palladium. The results show a cubic close-packed cluster structure for this material, in contrast to the icosahedral structure reported for Pd561(phen)60(OAc)180.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 27 (1993), S. 193-197 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 71.45.Gm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study collective excitations of π electrons in the fullerene molecule, by using the sum rule approach and linear response theory. The results for the excitation spectrum are discussed in relation to experimental data and to other theoretical approaches.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    ISSN: 1434-6079
    Keywords: 81.30.-t ; 61.14.-x ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Solid-liquid transition of fine tin particles having diameter of 2–10 nm is studied in-situ by high-resolution transmission electron microscopy under a ultra-high vacuum condition. Melting temperature is confirmed to decrease with the decrease of particle diameter. The particles less than the critical size, 2r c⋍5 nm, are found to have a specific phase between the solid and the liquid phase. The particle in this “pseudo-crystalline” phase contains crystalline embryos in it. Particles larger than the critical size have sharp liquid-solid transition, which completed within the time resolution of our microscope observation, 33 ms upon heating or cooling process. Large solid particles have Wulff's polyhedron, while particles around the critical diameter have rather spherical shape. Structural anomaly at the critical size occurs all over the outer most surface layer slightly below the melting temperature. Origin of the “pseudo-crystalline” phase and surface pre-melting phenomena are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 28 (1993), S. 61-65 
    ISSN: 1434-6079
    Keywords: 02.70.Lq ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have successfully identified stable configurations of both rare-gas and NaCl clusters with a new optimization procedure. An initial cluster configuration is prepared in a so-called shoot-and-stay process. Its total energy is then minimized with respect to the atomic coordinates. To prevent the system from being locked in local minima, the step size of each move is chosen as the width of the energy well at a higher level. As the system evolves, the global minimum is contained in the volume bounded by the decreasing value of step sizes. We have also carried out the optimization of NaCl clusters by the simulated annealing technique, for comparison. The results show that for such heterogeneous systems, the latter method cannot always find the global minimum, because of large energy gaps between different catchment regions in phase space.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 25 (1993), S. 253-259 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 32.80.pj ; 42.50.vk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ordered structures of two-species ions stored in a Paul trap are simulated by minimizing the total effective potential energy of the ion system. It is shown that the homo-charged two-species ion clusters display separating and mixing structures for different mass and charge ratios. The hetero-charged ion clusters consisting of one light negatively (positively) charged ion and three to six heavy positively (negatively) ions are found to exist stably, and the stability conditions obtained through the perturbative analysis indicate that the ion cluster consisting of more heavy ions has a looser limitation on mass and charge ratios of two-species ions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 246-248 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 75.60.Jp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The magnetization of an ensemble of free magnetic metal clusters in an inhomogeneous external magnet field is calculated. In particular we have investigated the effects of the combined lattice anisotropy and cluster rotation on the magnetic properties. If weak anisotropy is present, almost superparamagnetic behavior is obtained. For stronger anisotropies deviations from this are calculated as a consequence of spin resonance due to the anisotropy field and the cluster rotation. This was proposed recently by de Heer et al. to explain his experimental data as generally expected, since a rotating cluster in a static magnetic field should behave similarly than a nonrotating one in an oscillating magnetic field. The magnetization depends also sensitively on the relaxation times.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 249-251 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 61.16.Di
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The atomic force microscope has been used in the attractive (non-contact) force mode to produce images of individual nanometer-size clusters pre-formed in the gas phase and deposited on a wide variety of atomically-flat substrates. Using this technique, it is now possible to reliably image pre-formed clusters in their as-deposited positions. Studies of nanometer-size Au clusters supported on highly oriented pyrolitic graphite clearly show how the clusters are distributed across the scanned region. Cluster coverages inferred from atomic force studies are compared to those obtained from TEM studies of amorphous carbon grids simultaneously exposed to the same cluster beam.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 276-280 
    ISSN: 1434-6079
    Keywords: 33.80.−b ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The dynamics of excited states of cold Na3-clusters in a supersonic beam have been studied in time-resolved two-photon-ionization (TPI)-experiments, using picosecond pump&probe technique followed by mass-selective detection. In case of the electronically excited B-state for the first time the pseudorotational motion could be recorded as a temporal sequence. The time constant of pseudorotation was found to be 3ps. For the D-state, known to predissociate very rapidly, it was possible to directly ionize this excited electronic state. Decay times of the TPI-signal were estimated to be in the order of 2.7ps providing direct information of the fragmentation probability. Simultaneously the temporal evolution of the fragment signal Na 2 + was detected.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 13-16 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 34.20.Gj ; 34.40.+n ; 34.70.+e
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have measured absolute integral cross sections for low-energy collisions of atoms and molecules with neutral sodium clusters over a wide cluster size range (n=2–40). The cross sections are exceptionally large, reaching values of thousands of square angstroms. Consequently, the scattering involves long-range interactions. The van der Waals force, acting either alone (Nan+N2) or in concert with the inelastic charge-transfer “harpooning” channel (Nan+Cl2, Nan+O2) can describe the measurements. Using interaction parameters taken from spectroscopic studies of alkali clusters, we find very good agreement with the data. This provides a point of contact between beam scattering experiments and studies of cluster electromagnetic response properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 337-339 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 35.20.Wg ; 82.65.−i ; 68.45.Ax
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In order to modelize the CO dissociation observed on palladium particles, by means of Static Secondary Ion Mass Spectrometry, theoretical investigations were performed on small Pd clusters by using a local approximation of the density functional theory. Several types of defects were studied concerning their ability to dissociate the CO molecule.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 343-345 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Absolute cross-sections for photodetachment of negative carbon clusters are reported for C n − (n=3,...,8). These measurements are made using different types of ion sources, which create different isomers. These new results indicate that various negative and neutral isomers exist, some with electron affinities as low as ∼1 eV.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 340-342 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The combination of laser photodetachment of C 4 − and the Coulomb Explosion Imaging method was applied for the investigation of the structure of several C4 isomers and was correlated with their measured electron affinities.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 349-351 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.20.Sy ; 61.55.Dc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The combination of density functional (DF) theory with molecular dynamics (MD) allows one to simulate dynamical processes in solids, clusters and molecules without requiring a parameterization of the forces in the system. The method can also be used with the strategy of “simulated annealing” to determine structural isomers. We demonstrate the capabilities of the scheme in the case of the structure of neutral and charged phosphorus clusters, and discuss relationship between these structures and those of bulk systems (crystalline and amorphous). The results show clearly the tendency of phosphorus structures to have threefold coordination as well as “tubular” structures similar to that found in Hittorf's phosphorus (H-P). We discuss the interplay between electronic and geometric structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 355-357 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 73.20.Dx ; 63.20.Dj
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We use low temperature (10K) optical hole-burning and fluorescence line narrowing spectroscopy to investigate the electronic properties of CdSe nanocrystallites (quantum dots) as a function of crystallite diameter (20–80Å). We discuss how the homogeneous linewidth of the HOMO-LUMO transition, the energy shift between the absorbing and emitting state, and the LO phonon frequency vary with nanocrystallite size.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 377-381 
    ISSN: 1434-6079
    Keywords: 33.10.-n ; 33.70.Jg ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Spectral lineshapes of the electronic origin of tetracene·Arn (n=1–3,19) clusters have been simulated by the semiclassical spectral density method [L. E. Fried, S. Mukamel, J. Chem. Phys.96, 116 (1992)]. Information is obtained concerning the spectral shifts, the homogeneous linewidths and their temperature dependence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 388-390 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 05.45.+b
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The dynamics of clusters are revealed, in part, by the extent and nature of their chaotic and ergodic behavior. Conversely, small clusters offer opportunities to study the origins and evolution of chaotic and ergodic behavior. This investigation uses, as a probe, the time evolution of the distribution of sample values of the largest Liapunov exponent λmax. Two kinds of clusters are examined, Ar3 and Ar7. The distributionsg(λmax,E) allow inference of dynamical characteristics such as dwell times in the various potential minima and durations and frequencies of saddle crossings.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 65.40.Em
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The low temperature specific heat of the metal cluster molecular compounds Au55(PPh3)12Cl6, Pt309 Phen 36 * O30 and Pd561Phen37O200, with resp. 55, 309 and 561 core atoms are compared. ForT ∼ 1 K, Pt309 and Pd561 show a linear contribution toC/R of about 1/3 of the bulk value. A Poisson distribution of the electronic energy levels is suggested as an explanation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 54-57 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 79.60.−i ; 82.65.−i
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Metal clusters (Pb N ,Au N ) grow in a pulsed arc cluster ion source (PACIS). After supersonic expansion in the helium carrier gas the resulting beam is soft-landed under UHV conditions on either cold poly-cristalline silver,Si(111) or naturalSiO 2. Photoemission measurements with light from the synchrotron BESSY serve to investigate the electronic structure of the clusters. In this communication, valence band photoemission is presented forPb N onAg, Pb N onSi/SiO 2 andAu N onAg. After lead deposition, the valence band region exhibits only low, weakly structured intensity, whereas deposited gold clusters lead to the formation of a resolved narrow peak at 3.52 eV below ε F , which we attribute toAu 5d 5/2.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 61.14.−x ; 61.16.Di
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The structures of unsupported ultrafine silver particles in a molecular beam, produced by the inert-gas-aggregation technique, have been studied by electron diffraction. The dependence of particle structure on evaporation-source temperature (1260 °C ≤ Tc ≤ 1400 °C) has been investigated. Particles in the beam are found to divide into: a dominating proportion of small, decahedral particles, and a small proportion of unexpectedly large icosahedral particles, larger than any previously reported free icosahedra. The mean diameters are 2–3 nm and 7–10 nm, respectively. F.c.c. particles, with an average diameter of ∼6 nm, appear in significant numbers when Tc≥1350 °C. The particles' mean sizes and distribution widths increase with Tc. Electron microscope observations of particles collected from the beam support these findings.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 128-130 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 35.20.VF
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Ionization Potentials of LinHm clusters have been measured by photoionization. As in Lin, odd-even alternations and shell closing effects are observed. In a first approximation, we find that LinH clusters behave like Lin−1 and LinH2 like Lin−2. The results may be interpreted by assuming that the bonding of one hydrogen localizes one electron and that the other electrons remain delocalized.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 308-310 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.80 ; 33.60 ; 32.80F
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The photoionization dynamics of C60 has been studied by means of synchrotron radiation. The findings for single-photon ionization covering an energy range of 15 -120 eV are presented and contrasted with other experiments recently performed to elucidate the fragmentation and the ionization behaviour of fullerences as a result of relatively high energy impact. In this context, special emphasis is paid to the temperature dependencies, the actual ionization mechanism and the fragmentation behaviour of ionic C60.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 34.10.+x
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The dynamics of C60-rare gas collisions is studied using molecular dynamics with empirical two- and three-body forces. The carbon potential is chosen to be able to reproduce the experimentally determined bond lengths and cluster radius of C60 as well as the structure of small carbon clusters. The reaction channels observed can be divided into four categories: deep inelastic scattering, fragmentation, capture and inelastic scattering. The temperature dependence of the threshold energy for capture is studied and compared with available experimental data. The calculations predict a maximum in the lowest tail of the kinetic-energy distribution of the projectile with a transition from a single- to a double-humped maximum with increasing collision energy and, in addition, may provide a natural interpretation for the, as yet unexplained, structure in the experimental shapes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 28 (1993), S. 223-234 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.90.+s
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Fission of doubly charged silver clusters is investigated by the method of shell corrections. The following fission events are considered: Ag 22 2+ → Ag n + + Ag 22 −n + , (n=11, 10, 9, 8); Ag 21 2+ → Ag n + + Ag 21 −n + , (n=10, 9, 8, 7); Ag 18 2+ → Ag n + + Ag 18 −n + , (n=9, 8, 7, 6). It is found that the shell correction energy is comparable to or larger than the deformation energy of the liquid drop. Threshold energies for the fission events are calculated and compared with the experimental abundance spectra obtained by Katakuse et al. (1990). Correspondence between the calculated threshold energies with the shell corrections and the experimental abundance is very good, showing products from lower threshold fission channels yield more abundance. The threshold energies without the shell corrections are almost constant irrespective of the fission channels and cannot explain the experimental abundance. Abundance of some products are too small to be accounted for only by the threshold energies. The low abundance of those products may be explained by the presence of competing fission channels that have similar minimal energy paths. It is found in fission of Ag 18 2+ that the shell correction overwhelms the Coulomb energy and the fission channel to Ag8 + Ag 10 2+ is preferred over the fission channel to Ag 8 + + Ag 10 + .
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 28 (1993), S. 247-255 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 61.16.Di
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Multislice calculations have been performed for Ag, Pd and Au clusters in the size range of ≃ 5.0 nm diameter of cuboctahedral, icosahedral and decahedral structures. It could be shown that tilt series are necessary for the classification of the structures. Particularly for arbitrary orientations, i.e. deviations from main directions such as 2-, 3- and 5-fold axes, the performance of computer simulations is mandatory. The influence of absorption is also studied for the case of a 100 kV microscope by introducing a complex potential.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 25 (1993), S. 239-246 
    ISSN: 1434-6079
    Keywords: 31.20.Di ; 33.80.Gj ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The potential energy surface (PES) of linear Ar 3 + is calculated at the MP4/6-31G* level including all single, double, triple and quadruple excitations. The results show that the PES of the linear Ar 3 + has a very flat valley along the asymmetric stretching vibration normal mode, ν3. A higher level quadratic configuration interaction calculation including single, double and triple substitutions QCISD (T) along this flat valley suggests that an asymmetric geometry energy minimum reported earlier based on MP2 [1] is due to symmetry breaking in UHF. The global minimum of the PES is found to be for the symmetric geometry atR ab =R bc =2.66±0.01 Å, which is in good agreement with the MRD-CI calculation [2] and expectations from our earlier photodissociation experiments [3]. The calculational results are compared with other theoretical calculations, and are discussed in the context of the photodissociation and dynamics of dissociation experiments conducted on Ar 3 + .
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 25 (1993), S. 267-273 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 82.40.Dm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Kinetic studies of the reactions of neutral lead clusters with NO2, NO and O2 were performed at 300 K. Reaction with NO2 is rapid, with the observed second-order rate constants for most clusters being between 0.2 and 5 × 10−11 cm3/s. There is a general trend of increasing rate with cluster size, although a few clusters display unusually high or low rates compared to ones of neighboring size. The reactions with NO are considerably slower by factors ranging from about 5 to 10. Reaction products are observed by laser ionization at 193 and 222 nm in conjunction with time-of-flight mass spectrometry. At lower fluence, the association products Pb x (NO2)+ and Pb x (NO2) 2 + are observed in the case of reactions with NO2. At higher laser fluence, Pb x + and Pb x O x −1+ dominate the mass spectra of Pb x reactions with NO2, showing that the products fragment to more stable oxides. No reaction with oxygen was observed for any cluster, setting upper limits on the rates of 5 × 10−14 cm3/s.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Molecular dynamics calculations have been performed to simulate the low energy collision (0.2 eV) of a rare gas atom (He, Ar, Xe) with a cluster of 125 argon atoms. Depending on its relative mass to argon, the projectile is either deflected (He) or captured (Ar, Xe) by the argon cluster. We have determined the deflection function of the He projectile that is scattered, and for Xe we have determined wether it stays near the surface of the cluster or migrates inside. These results have been discussed in the light of very simple models.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 64-68 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 61.60.+m ; 31.20.Pv
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The classical naked cluster ions of the post-transition elements that are stable in solid compounds and their lower charged analogues observed in mixed metal beams reflect the reduced number of good bonding orbitals. New cluster ions of indium that are hypoelectronic (fewer than 2n+2 skeletal bonding electrons) because of distortions or the bonding of heterometal atoms within the clusters are described. A large family of new, orbital-rich clusters of the group III and IV transition metals sheathed by halide are all centered by a wide variety of heteroatoms. Factors in their stability, possible analogous naked cluster targets, and some calculations are considered.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 98-100 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.60.Cv
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have measured the photoelectron-spectra of I− (H2O)n clusters in the size range n=1–60. We have found that the first six water molecules form a solvation layer with an average 0.35 eV electrostatic stabilization of the anion. At larger cluster sizes the electrostatic stabilization of water does not fit a continuous dielectric solvent. The most stable structures of the clusters consist of internally solvated anions. In the size range n=34–40 we have found evidence for existence of cluster structures with surface solvated anions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.35.-q ; 33.25.-j
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Fullerenes containing metal atoms and clusters can be formed by the arc-vaporization method. The electronic structure of these metallofullerenes can be probed using magnetic resonance techniques. Electron paramagnetic resonance (EPR) spectra of LaC82, YC82, ScC82 and Sc3C82 have been obtained. Metallofullerenes containing a single metal atom (MC82 with M = La, Y, or Sc), have small hyperfine couplings and g-values close to 2, implying that they can be described as + 3 metal cations within — 3 fullerene radical anion cages. In the La and Y cases, additional EPR active MC82 species have been found. The EPR spectrum of Sc3C82 shows that the metal atoms are equivalent, suggesting that they may form a triangular molecule. No EPR spectrum is found for Y2C82 or for Sc2C2n species (with 2n = 82,84,86), suggesting that they are diamagnetic. Sc NMR spectra of a solution containing Sc2C2n species have been obtained which confirm the diamagnetism of the discandium metallofullerenes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 187-188 
    ISSN: 1434-6079
    Keywords: 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Large sodium clusters, up ton=21, generated by a low-temperature modification of the laser ablation gas jet source were ionized with two photons of visible radiation from an amplified picosecond dye-laser system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 25 (1993), S. 181-184 
    ISSN: 1434-6079
    Keywords: 42.65.An ; 36.40.+d ; 71.45.Gm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Motivated by a discrepancy of five orders of magnitude between three different hyperpolarizability measurements on the C60 fullerene, we calculated the optical response of this cluster using a tight-binding Hamiltonian and compared the results to those for a benzene molecule. Our Hamiltonian reproduces the linear polarizability and hyperpolarizability of benzene reasonably well. For C60, our calculations of the bare polarizability agree only with two of the optical response measurements and indicate that the corresponding linear and nonlinear response of C60 is much larger than that of C6H6. We find that screening effects decrease this difference strongly, and also reduce the calculated hyperpolarizability of C60 to a value which is two orders of magnitude below the favored measurements.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 59-63 
    ISSN: 1434-6079
    Keywords: 79.70.+q ; 03.65.-w ; 36.40.+d ; 61.16.Di
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The quantized energy levels of electrons in supported nanometer-size Au clusters have been resolved at room temperature using field emission techniques. By studying the time dependence of the electron emission current from an individual supported cluster, information about the structural stability of the cluster can also be obtained. Studies show abrupt jumps between different emission rates that are revisited as time progresses. This phenomenon can be attributed to a rearrangement of the cluster structure and/or orientation on the substrate and provides new evidence of multiple ‘isomeric’ structures for small clusters of metallic atoms.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    ISSN: 1434-6079
    Keywords: 31.70.Ks ; 36.40.+d ; 71.20Hk ; 31.20.Sy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe the results of extensiveab initio molecular dynamics calculations of the properties of fullerenes and microtubules. Our finite temperature quantum MD simulations for solid C60 are in excellent agreement with NMR, photoemission and neutron scattering data. The C60 isomer containing two pairs of adjacent five-fold rings has a binding energy only 1.6 eV smaller than that of perfect C60, but the transformation between these two structures is hindered by a 5.4 eV barrier. It thus requires high temperatures and long annealing times. High temperatures are also needed for the transformation of the lowest energy C20 isomer, a dodecahedron, to a corannulene structure, which can be thought of as a fragment of C60. The corannulene structure is a natural precursor for the formation of C60. Simulations of reactions show that C2 can insert into C58, perfect C60, and defect C60 fullerenes without an activation barrier, while C3 attaches only to their surfaces. Evaporative fragmentation of carbon clusters during annealing is unlikely, but atom and fragment exchange during collision favor "locally" most stable structures, such as C60. These results may explain the large increase in the abundance of C60 and C70 when carbon clusters are annealed at high density. We have also carried out calculations for paradigmatic microtubules, both reflection-symmetric and chiral. We find that the optimized geometries of the tubules are close to the ideal ones. It is possible to fabricate tubules with direct band gaps away from the Γ point by exploiting the similarities between the projected band structure of graphite and that of the tubule. The semiconducting tubules can be doped n- and p-type by substitutional N and B, respectively.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 110-114 
    ISSN: 1434-6079
    Keywords: 34.10.+x ; 36.40.+d ; 82.20. Fd ; 82.20. Wf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The interaction (modelled by a LEPS potential) of a D2 molecule with an icosahedral Ni13 cluster is mapped and analyzed in the form of equipotential contour plots. The topological features of the map correlate with the energetic and dynamical characteristics of the dissociative adsorption of the molecule on the cluster, which were extracted from quasiclassical trajectory simulations. A modification of the LEPS potential used originally is introduced. It brings the calculated reactivity of the cluster into agreement with the experimental data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 126-130 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 42.65.-k ; 73.20.Dx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Size effects in femtosecond photon echo spectroscopy of neat clusters are calculated using a quasiparticle representation of the nonlinear response. We extend our previous study of cooperative effects on the nonlinear response of assemblies of two level molecules [J. A. Leegwater and S. Mukamel, Phys. Rev. A46, 452 (1992)] to allow for nuclear motion and to have an s-p model of polarizable atoms. Photon echos in Benzene/Argon clusters are calculated using a semiclassical phase averaging procedure [L. E. Fried and S. Mukamel, Adv. Chem. Phys. (in Press)].
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 25 (1993), S. 175-180 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.20.Sy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The electronic structure of C60 doped with thep-elements B-F, Al-Cl and Ga-Br located at the centre of the cage has been analyzed within the local density approximation using the von Barth-Hedin exchange correlation potential. The calculations show the existence ofn- andp-type doped Buckminsterfullerene, where a partly occupied level occurs in the band gap, similar to the donor or acceptor levels in traditionally doped semiconductors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 119-125 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 31.20.Sy ; 32.80.Dz ; 71.10.+x
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Theoretical investigations of size evolutionary patterns for multiply charged anionic metal clusters and solvation of sodium in water clusters are discussed. For Na N Z- clusters, energetic stability and electron decay channels are determined. Formation of a “surface Rydberg-like state” in Na(H2O) N , correlating with calculated and measured ionization potentials, is analyzed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 26 (1993), S. 138-140 
    ISSN: 1434-6079
    Keywords: 36.40.+d ; 33.20.Lg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The optical absorption of small mass selected Agn-clusters (n=8–39) embedded in solid Ar, Kr and Xe has been measured. Strong absorption has been found between 3 and 4.5 eV. The absorption spectra show 1 to 3 major peaks depending on the cluster size. The width of these peaks is smaller than in gas phase photodepletion experiments of silver ions, most likely due to the low and well defined temperature of the clusters in the matrix. The results are compared to a simple model based on a Drude metal, taking into account the spillout of the electrons and allowing for a deviation of the cluster from a spherical shape. Absorption cross sections scale with the number of valence electrons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    ISSN: 1434-6079
    Keywords: 78.40.Fy ; 36.40.+d ; 33.20.Kf ; 33.20.Lg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Absorption spectra have been recorded for gas phase, size-selected neutral silicon clusters using resonant one- and two-color photodissociation spectroscopy. We now have spectra between 0.94 – 5.58 eV for clusters containing up to 70 atoms. Starting at ∼15 atoms, the spectra are all amazingly identical. Comparisons of the silicon cluster spectra to those of various forms of bulk silicon show that the cluster spectra have much in common with the spectrum of the most stable diamond structure of bulk crystalline silicon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...