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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 1295-1303 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Experimental ionization potentials (I) and electron affinities (A) of metal clusters MeN are compiled for a variety of systems and their size dependence is analyzed. In the theoretical part, we perform semiclassical density variational calculations using the spherical jellium model and the local density approximation. For alkali systems and, to some extent, also for some nonalkali systems, the calculated values of I and A reproduce very well the average size dependence of the measured quantities, if their common bulk limit W is adjusted to the experimental bulk work function. This holds even for rather small systems where I and A are no longer linear in N−1/3. We discuss the extent to which classical models for the energetics of charged metal spheres can account for the correct size dependence in the large-cluster limit. We point out that the deviation of the slope parameters α and β in the asymptotic expressions I∼W+α(e2/rs)N−1/3, A∼W−β(e2/rs)N−1/3 from the values (1)/(2) , which depends on the material via the Wigner–Seitz parameter rs, can be entirely accounted for by quantum-mechanical effects, namely the kinetic, exchange, and correlation energies and the diffuseness of the electron density.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7682
    Source: AIP Digital Archive
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Chaos 5 (1995), S. 317-329 
    ISSN: 1089-7682
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The quantum density of states of the Hénon–Heiles potential displays a pronounced beating pattern. This has been explained by the interference of three isolated classical periodic orbits with nearby actions and periods. A singular magnetic flux line, passing through the origin, drastically alters the beats even though the classical Lagrangian equations of motion remain unchanged. Some of the changes can be easily understood in terms of the Aharonov–Bohm effect. However, we find that the standard periodic orbit theory does not reproduce the diffraction-like quantum effects on those classical orbits which intersect the singular flux line, and argue that corrections of relative order (h-dash-bar) are necessary to describe these effects. We also discuss the changes in the distribution of nearest-neighbor spacings in the eigenvalue spectrum, brought about by the flux line. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 315 (1984), S. 341-347 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The single-particle densityρ(r) of a system of fermions can be calculated in a tractable way as the Laplace inverse of the Bloch density describing the system. The complex integrals involved can be solved very easily by the saddle-point method. The semiclassical nature of this approach is illustrated in the simple example of the single-particle level density of a harmonic oscillator potential. It is then applied to calculate the total energy of particles in different mean field potentials. The exact Bloch density being generally unknown, different approximate forms are used in our calculations which correspond to a partial resummation of the Wigner-Kirkwoodħ-expansion. The resulting local densities reproduce the exact density distributions on the average, without quantal oscillations. They are well defined everywhere, even beyond the classical turning point, in contrast to the original Wigner-Kirkwood approach.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 296 (1980), S. 87-90 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Wigner-Kirkwoodℏ-expansion of the Wigner transform of the Bloch density can be resummed in the case of non local potentials if we keep only up to second order derivatives of the Wigner transform of the non-local potential with respect to the phase space variables. We also investigate a second approximation to the Bloch density where care has been taken with respect to a consistentℏ expansion. For a one dimensional example we calculate the smooth part of the density and the corresponding energy demonstrating that both approximations to the Bloch-density yield well defined average densitiesand energies.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 41 (1995), S. 10-14 
    ISSN: 1432-1432
    Keywords: Microsatellite ; DNA polymorphism ; Primate phylogeny ; DNA sequencing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We amplified, via PCR, DNA segments from intron 1 of the tyrosine hydroxylase gene (TH01) and intron 40 of the von Willebrand factor gene (VWA) in ten nonhuman primate genera. In humans both introns contain polymorphic microsatellites with tetrameric repeats. Compared to the allelic ranges in human populations relatively short repeat arrays could be detected for the nonhuman primates typed, presumably reflecting an ancient precursor state at both microsatellite loci. Furthermore, our results provide evidence for an association of the average number of repeats present in different primate genera and their divergence time from man. DNA sequencing of VWA orthologues revealed a relatively high variability in the arrangement of repeats in the 5′-repeat arrays, the generation of which could probably be explained by polar mutational events.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 319 (1984), S. 159-165 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We discuss the exact solution of the time-dependent Schrödinger equation for a system of two crossing levels with a residual interaction. In contrast to the familiar Landau-Zener (LZ) solution used in most applications, we allow for more general boundary conditions; in particular we treat explicitly the case of afinite interval around the crossing point. The exact jumping probability is shown to be extremely sensitive to these boundary conditions; in many realistic cases it is found to be smaller than the LZ value by several orders of magnitude. We also compare the exact excitation energy to the one obtained in the usual cranking approach.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 319 (1984), S. 205-213 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In heavy nuclei where the thickness of the diffused edge is relatively small, a certain sharp effective surface can be defined which characterizes the shape of the nucleus, and it can be considered as a collective dynamic variable. It is shown that the problem of fluid dynamics can be simplified by reducing it to simple linearized equations for the dynamics in the nuclear interior and boundary conditions set at the effective dynamic sharp surface of the density distribution. These conditions are derived from the fluid dynamical equations. Transitional densities obtained from this simple model are compared with the numerical solution of fluid dynamical equations.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 349 (1994), S. 219-222 
    ISSN: 1434-601X
    Keywords: 21.60.Jz ; 36.40.+d
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We discuss and compare the gross features of resonance excitations in nuclei and metal clusters. We point out the phenomenon of ”jellium scaling” which means that different materials for metal clusters all give similar resonance spectra and we discuss the various effects which determine the exact position of the resonance.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 297 (1980), S. 247-256 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the semiclassical kinetic energy density functionalτ[ρ] for deformed nuclear shapes. Using Strutinsky-averaged quantities as reference, we demonstrate that the functionalτ[ρ] is able to reproduce the averaged kinetic energies very accurately, even at very large deformations.
    Type of Medium: Electronic Resource
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