ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
Language
Number of Hits per Page
Default Sort Criterion
Default Sort Ordering
Size of Search History
Default Email Address
Default Export Format
Default Export Encoding
Facet list arrangement
Maximum number of values per filter
Auto Completion
Topics (search only within journals and journal articles that belong to one or more of the selected topics)
Show more topics
Feed Format
Maximum Number of Items per Feed
Permalink If you want to be able to use settings permanently, you must save your settings and then set a Bookmark to the permalink
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Dependence of metal cluster reaction kinetics on charge state. II. Chemisorption of hydrogen by neutral and positively charged iron clusters (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 6605-6610 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The kinetics of D2 chemisorption by gas-phase neutral (Fex ) and positively charged (Fe+x) iron clusters has been studied under identical reactor conditions. Similar to the neutrals, the reaction rate for the ions displays a nonmonotonic dependence on x, varying by more than four orders of magnitude between x = 1 and x = 31. The presence of the positive charge is found to have a substantial influence on reaction rate for the majority of clusters in the 1–31 atom size range. Clusters containing 4–6 and 〉17 atoms experience an enhancement in rate while in contrast those containing 3 and 9–14 atoms experience a decrease in rate. Further, studies of H2 chemisorption onto Fe+x (x = 4–22) indicate an enhanced, cluster size-dependent isotope effect for the cluster ions which is quite similar to that previously observed for Fex. The effect of the positive charge on D2 chemisorption reactivity is explained within the framework of the frontier orbital model of activated chemisorption by invoking an "effective'' activation barrier for Fe+x which incorporates the electrostatic interactions arising from the nonzero charge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454448
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    CO chemisorption on free gas phase metal clusters (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 111-119 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Pulsed fast flow reactor techniques have been used to study the reactivity of CO toward clusters of many different transition metals; V, Fe, Co, Ni, Cu, Nb, Mo, Ru, Pd, W, Ir, and Pt as well as Al, for clusters containing up to 14 atoms. Clusters are produced by pulsed laser vaporization of metal substrates, injected into the reactor, formed into a molecular beam, and detected by photoionization time of flight mass spectrometry. Our results show that CO is readily chemisorbed on most transition metal clusters containing five or more metal atoms, and that the reactivity for larger clusters varies by a factor of 2 or 3, depending on both cluster size and metal type. Depending on the metal, certain atoms, dimers, trimers, and tetramers exhibit little evidence of reactivity toward CO. This observation is explained in terms of a competition between unimolecular decomposition and collisional stabilization, and leads to a prediction of the ordering of the metal–CO bond strengths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454643
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Dependence of metal cluster reaction kinetics on charge state. I. Reaction of neutral (Nbx) and ionic (Nb+x, Nb−x) niobium clusters with D2 (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 3555-3560 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The effect of charge state on niobium cluster chemisorption kinetics is explored via measurement of the relative rates of D2 activation by Nb−x, Nbx, and Nb+x containing up to 28 atoms. The presence of the + or − charge is found to have only a minor effect on rate for the majority of the clusters, with the reactivity of the ions being generally within a factor of 2.5 of the corresponding neutrals. The excess charge does, however, have a profund influence on reaction rate for a number of clusters in the 7≤x≤16 size range, which may be indicative of the importance of cluster electronic structure in the chemisorption process. Kinetic data for Nb9, Nb12, and Nb+12 are found to deviate significantly from the expected pseudo-first-order behavior, suggesting the existence of structural isomers for these species. The anomalous behavior for Nb9 and Nb12 was not observed in previous neutral Nbx chemisorption studies. The maximum uptake of D2 by niobium clusters is found to be essentially independent of charge state, but varies strongly with x, consistent with the presence of a high barrier to D–D bond activation for certain of the clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453903
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Electron binding and chemical inertness of specific Nbx clusters (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1697-1698 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Photoionization threshold measurements on niobium clusters Nbx x=4–29, reveal an unprecedentedly strong dependence on x, the number of atoms in the cluster. Major maxima in threshold energies occurring at x=8, 10, and 16 correspond to those clusters recently shown to be unreactive toward molecular deuterium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451214
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Infrared spectroscopy of unsupported metal cluster complexes using multiple photon dissociation (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1198-1199 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451316
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Aluminum clusters: Magnetic properties (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 4651-4656 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We report the first measurement of the magnetic moments of gas phase aluminum clusters ranging in size from 2 to 25 atoms. Aluminum clusters are produced by pulsed laser vaporization of an aluminum rod inside the throat of a high pressure pulsed nozzle. The highly collimated cluster beam is passed through a Stern–Gerlach magnet and the deflected beam is analyzed by spatially resolved photoionization time-of-flight mass spectrometry. Aluminum clusters less than nine atoms in size are found to have magnetic moments generally consistent with those predicted from spin and orbital moments of the ground electronic states. As expected, a general trend toward reduced magnetic moment per atom with increasing cluster size is observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449991
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Zero electron kinetic energy spectroscopy of Au−6 (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 4102-4105 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Zero electron kinetic energy (ZEKE) spectroscopy and photodetachment cross section measurements have been carried out on Au−6. The transition frequencies of ZEKE peaks and resonance peaks are nearly identical, consistent with the proposal that the excited negative ion of Au6 has a geometry quite similar to that of neutral Au6, and supporting the picture of the resonances as weakly bound "surface states.'' From these studies the 0–0 transition frequency between Au−6 and Au6 is measured to be 16 541±17 cm−1, and the vibrational frequencies for the neutral Au6 ground state, the Au−6 ground state, and the (Au−6)* anion excited electronic state are 107, 73, and 107 cm−1, respectively. Lastly, we observe evidence for a previously unreported resonance transition to the excited anion which we suggest is the 0–0 transition of Au−6 to (Au−6)*.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461865
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Gas-phase rhodium cluster chemistry: Influence of adsorbate electronic structure on reaction rate (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 1201-1202 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455234
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Palladium clusters: H2, D2, N2, CH4, CD4, C2H4, and C2H6 reactivity and D2 saturation studies (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 254-261 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this paper both deuterium saturation measurements and gas-phase kinetic measurements of chemisorption of H2, D2, N2, CD4, CH4, C2H4, and C2H6 on neutral palladium clusters are reported. Saturation studies with D2 show that small palladium clusters can bind up to three deuterium atoms per palladium atom in the cluster, in contast to H/M ratios near unity typically reported for metal surfaces. In addition, the small palladium clusters exhibit pronounced discontinuities in deuterium uptake which may be indicative of structural transformations or selective desorption of deuterium. From the kinetic studies we find that, in general, the rate constants for a given size cluster towards different reagents tend to order as D2, H2〉N2〉C2H4〉CD4, CH4, C2H6. The shape of the reactivity pattern with the different reagents varies strongly with cluster size for clusters containing less than 25 atoms. Finally, an inverse hydrogen isotope effect is observed for both hydrogen and methane, i.e., the D2 and CD4 rate constants are significantly larger than those of H2 and CH4, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458472
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Size-selective dehydrogenation of benzene by gas-phase niobium cluster ions (Nb+x) (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 5943-5947 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The gas-phase reaction of positively charged niobium cluster ions Nb+x with normal and perdeuterobenzene has been studied using a fast-flow reactor and direct ion sampling techniques. Chemisorption of benzene onto the ion is facile, with the rate being essentially independent of x. However, both the resulting product distributions, consisting of species NbxC6H+m and NbxC6D+m with m=0,2,4,6, and the relative product yields not only display a dramatic dependence on cluster size, but are also remarkably similar to those previously observed for neutral Nbx using gentle, low-fluence, single-photon 6.42 eV photoionization. Direct observation of products with m≤6 indicates that both chemical dehydrogenation of benzene and desorption of hydrogen from the cluster ions must occur in the fast-flow reactor. Further, the relative yield of dehydrogenated products is found to increase substantially with increase in cluster "temperature.'' Complete dehydrogenation of benzene to m=0 is also found to occur for niobium cluster oxides NbxO+ containing 5–14 Nb atoms. The present results are discussed in terms of the mechanism of the dehydrogenation process, as well as with respect to their relevance in determining "true'' parent product distributions formed in reactions of the corresponding neutral clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454507
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...