Numerical comparison between relativistic and nonrelativistic theory for scattering of slow electrons from atoms

Abstract

By means of the results for phase shifts, differential cross-sections, and spin polarization in scattering of slow electrons from screened Hg, Xe and Ar nuclei the Motttheory is compared with its nonrelativistic approximation. For electron energies below 200 eV we find an increasing agreement of the results of the two theories with decreasing atomic number of the scatterer; for Ar both theories yield the same result.W.H. R6hl, Institut ffir Theoretische Physik der Universit/it K61n and Institut de Physique Nucl6aire, Division de Physique Th6orique, Orsay: The Deviation of the Magnetic Moments from the Schmidtlines Induced by a Nonlocal Two-Body Potential A unitary transformed two-body hard-core potential contains nonloeal terms, which will produce a deviation of the magnetic moments from the Schmidt-lines. These deviations were calculated for several nuclei up to Ca 41 using an oscillator basis, and they are positive for odd-neutron and negative for odd-proton nuclei. Thus it is not possible to describe the experimental deviation from the Schmidtlines; but for the magnetic moments of C 13, 015 and N is, the only nuclei where the experimental values are outside of the Schmidtlines, these nonlocal terms yield the right magnitude in the right direction of the deviation.A. Imbusch, I. Physikalisches Institut der Technischen Universit/it Berlin: t)ber den Einflufl der Oberfliichen diinner Schichten anf die Energieverluste schneller Elektronen in AI (The Influence of Surfaces on the Energy Losses of fast Electrons Traversing Thin Al-films The characteristic energy losses of electrons traversing thin Al-films were measured with high resolution. Especially their dependence on film thickness was investigated. To interpret satisfactory the observed dispersion of surface plasma loss retardation effects had to be taken into account. Furthermore, energy losses in the low energy part of spectrum, e.g. the intraband energy loss of A1, are shown to be surface losses in terms of the dielectric theory.

Spin polarization and cross sections of electrons elastically scattered from heavy alkaline-earth atoms

“…For a central potential, the Dirac equation can be reduced to a set of two equations similar to the form of the Schr6-dinger equation such as [6][7][8][9] g?,, + 2-e(e+ 1)/r 2-U? (r)lg~ (r) = 0.…”

A Relativistic Theory of low Energy Electron Diffraction

“…A detailed presentation of this formalism has been given by Meister (1962}. Although the covariant spin formalism shows· its power mainly at relativistic energies, we prefer it, for the present low energy purpose, to an 11 ordinary" spin formalism (cf. e.g.…”