Studies in the electronic structure of matter

Thesis/Dissertation · Mon Jan 01 00:00:00 EST 1979

OSTI ID:6336738

Swarts, C A

Chapter I: Here the results of various theories for the angular distribution of electrons photoemitted from the outermost p-shell of rare gas atoms are compared. The theories compared are (I) the local density theories of Slater (X/sub ..cap alpha../) and of Hohenberg, Kohn and Sham, (II) the pseudopotential method, (III) Hartree-Fock theory as evaluated by Kennedy and Manson, and (IV) Amusia's Random Phase Approximation with Exchange (RPAE). It is shown that the local density theories, although simple, generally fail to produce reliable cross section; the more complicated Hartree-Fock method is no more reliable; the a priori RPAE method is most reliable, but tedious; and the phenomenological pseudopotential method offers a good combination of reliability and simplicity. The muffin-tin approximation, widely used in molecular and condensed matter physics, is examined and found to be adequate. Chapter II: Extended Hueckel theory is applied to GaAs, GaP and to the nitrogen isoelectronic trap in GaAs and GaP. The computed perfect crystal band structures are found to be in reasonable agreement with those computed with empirical pseudopotentials. Nitrogen impurity levels in GaAs and GaP are calculated using a cluster model. Chapter III: By means of model calculations for an independent electron metal, we obtain exact lineshapes for the photon absorption, emission and photoemission spectra of deep core states. We find in each case an X-ray edge anomaly as pedicted by Nozieres and De Dominicis. Sumrules are used as a general check on the calculations and to explain the deviations of the exact theory from the exciton theory away from threshold.

• Research Organization: Illinois Univ., Urbana (USA)
• OSTI ID: 6336738
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
RARE GASES
PHOTOEMISSION
GALLIUM ARSENIDES
ELECTRONIC STRUCTURE
GALLIUM PHOSPHATES
ANGULAR DISTRIBUTION
COMPARATIVE EVALUATIONS
ELECTRONS
HARTREE-FOCK METHOD
MUFFIN-TIN POTENTIAL
RANDOM PHASE APPROXIMATION
SLATER METHOD
IMPURITIES
NITROGEN
VALENCE
ABSORPTION SPECTRA
EMISSION SPECTRA
METALS
SUM RULES
ARSENIC COMPOUNDS
ARSENIDES
DISTRIBUTION
ELEMENTARY PARTICLES
ELEMENTS
EMISSION
EQUATIONS
FERMIONS
FLUIDS
GALLIUM COMPOUNDS
GASES
LEPTONS
NONMETALS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PNICTIDES
POTENTIALS
SECONDARY EMISSION
SPECTRA
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory