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  • 1
    Electronic Resource
    Electronic Resource
    Positron trapping rate into vacancy clusters (1979)
    Springer
    Applied physics 20 (1979), S. 181-184 
    Details
    ISSN: 1432-0630
    Keywords: 71.60.+z ; 78.70.Bj
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The trapping rate of positrons into vacancy clusters in metals has been calculated. It increases with the trap size and binding energy and approximately scales with the number of vacancies in small clusters. The phonon-mediated contribution to the trapping rate is small. The temperature dependence of the trapping process is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00885942
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  • 2
    Electronic Resource
    Electronic Resource
    Monte-Carlo calculations of keV electron and positron slowing down in solids (1983)
    Springer
    Applied physics 32 (1983), S. 95-106 
    Details
    ISSN: 1432-0630
    Keywords: 61.80 ; 78.70 ; 29.70
    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 Monte-Carlo simulation technique based on the screened Rutherford differential cross section for the elastic scattering and Gryzinski's semiempirical expression for the inelastic core and valence electron excitation is used to describe electrons and positrons slowing down in solids. The theoretical results are compared with the experimental backscattering, absorption and transmission results for aluminum, silicon, copper, and gold thin film and semi-infinite targets and good agreement is observed. The simulated stopping profiles are fitted with a simple analytic expression. The profiles are Laplace-transformed to give a useful data base for analyzing phenomena associated with slow positron re-emission from solids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00617834
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  • 3
    Electronic Resource
    Electronic Resource
    Positron detrapping from defects: A thermodynamic approach (1981)
    Springer
    Applied physics 26 (1981), S. 93-100 
    Details
    ISSN: 1432-0630
    Keywords: 71.60+Z ; 78.70B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The rate of positron detrapping in thermal equilibrium from lattice defects has been calculated by relating it to the specific trapping rate. The results for vacancies, dislocations and surfaces each show a different temperature dependence for the escape rate. For vacancies a measure of the importance of the detrapping can be obtained from the ratio of the vacancy formation energy to the positron binding energy in the defect. The positronium desorption rate from a surface is also calculated and agreement with experimental results is found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00616655
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of plastic deformation on positron lifetime spectra in alkali halides (1974)
    Springer
    Applied physics 5 (1974), S. 41-43 
    Details
    ISSN: 1432-0630
    Keywords: Positron annihilation ; Alkali halides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Positron lifetime spectra have been measured in plastically deformed KCl and NaCl single crystals. The experiments indicate that a third component of the order of 2 nsec is produced by the deformation, and its relative intensity (2–4%) is only weakly dependent on the degree of deformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01193392
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  • 5
    Electronic Resource
    Electronic Resource
    Computer simulations studies of the catalytic oxidation of carbon monoxide on platinum metals (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 4380-4386 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The steady-state catalytic oxidation process of carbon monoxide on platinum metal surfaces is studied using two irreversible kinetic computer simulation models: (a) An extended version of the model introduced by Ziff, Gulari, and Barshad (ZGB) with the effects of CO desorption and diffusion as well as finite reaction probability taken into account. The different physical processes, diffusion and desorption are studied independently and their effect on the equilibrium window, i.e., the regime where steady CO2 formation occurs is determined. (b) An interaction model where adatom–adatom nearest-neighbor (nn) interactions are taken explicitly into account through Boltzmann terms J1, J2, and J3 which are the energies of the CO–CO, O–O, and CO–O interactions, respectively. The phase diagrams in the temperature–CO-partial pressure (T,pCO−) plane are determined for different values of the nn interactions. The behavior of the system is dependent on the sign of J1(=J2 in the simulations) as well as the sign of the difference J1−J3. There is thus a clear analogy with a two-component equilibrium lattice gas with nn interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456818
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  • 6
    Electronic Resource
    Electronic Resource
    Residual resistivity of vacancies in simple metals
    Amsterdam : Elsevier
    Physics Letters A 63 (1977), S. 60-62 
    Details
    ISSN: 0375-9601
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0375-9601(77)90609-0
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  • 7
    Electronic Resource
    Electronic Resource
    A possibility of gravitational force shielding by bulk YBa"2Cu"3O"7"-"x superconductor
    Amsterdam : Elsevier
    Physica C: Superconductivity and its applications 203 (1992), S. 441-444 
    Details
    ISSN: 0921-4534
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0921-4534(92)90055-H
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  • 8
    Electronic Resource
    Electronic Resource
    Monte Carlo study of CO hydrogenation on cobalt model catalysts (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 7674-7682 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Useful information on catalytic reactions can be achieved using Monte Carlo simulations combined with experimental data from model catalysts. We present a comprehensive analysis of the simulation studies of CO hydrogenation on a hexagonal surface using a discrete computer model for the irreversible reaction kinetics with no interactions between the surface species but their mutual reactions. The simulation results are compared to experimental data from a cobalt foil model catalyst at 101 kPa and 525 K. As a result, the following microscopic picture of the reaction on the catalyst surface is extracted: the rate-limiting reaction step is the termination of the carbon chains (α-hydrogenation), hydrogen atoms occupy different adsorption sites from other reactants, and the diffusion of hydrogen along the surface is fast. The model is also used to address the relevance of the ensemble effects for CO dissociation and the surface sensitivity of the CO hydrogenation reaction. Our simulation results imply that these aspects have little effect on the rates of hydrocarbon formation. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469019
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  • 9
    Electronic Resource
    Electronic Resource
    Structure of CAl12 (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 8075-8080 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The structures of an isolated CAl12 cluster and a solid composed of CAl12 clusters have been studied using the Car–Parrinello method, based on the density functional theory and the local density approximation. We have compared the results of using the ultrasoft Vanderbilt pseudopotential with those of both a traditional pseudopotential and a linear combination of atomic orbitals method. We have confirmed the high stability of the cluster in its icosahedral structure. However, we show that the cluster-assembled solid is unstable against melting of the clusters, as previously found for SiAl12. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.470172
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  • 10
    Electronic Resource
    Electronic Resource
    A Monte Carlo study of CO oxidation with oscillations induced by site blocking (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 2038-2044 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We show that introduction of an additional adsorbate with appropriate adsorption and desorption rates leads to sustained oscillations in the CO oxidation on a catalytic surface. The adsorbate does not participate in the formation of CO2, but only blocks sites. We speculate on the possibility of experimental verification of our results by calculating the properties that the extra adsorbate should have. We have studied the reactions using a master equation that we have solved with the dynamical Monte Carlo method, using macroscopic rate equations, and using a combination of these two. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473310
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