Studies in the electronic structure of matter

CHAPTER ONE: KLL Auger transition rates for helium are computed using simple atomic orbital wavefunctions which take into account the difference in average electron-electron repulsion of initial and final states. The results are consistent with transition rates computed by other authors using a variety of many-electron techniques. It is suggested that wavefunctions determined in the manner described provide a useful representation of the autoionizing state within the first Bohr radius. CHAPTER TWO: A method for extracting atomic pseudo-potentials from photoelectron angular distributions is described and applied photoionization of the outermost p shells of Ar, Kr, and Xe and to the 4d shell of Xe. The pseudopotentials obtained reproduce the data, and also predict accurate cross sections and phase shifts for photoelectron energies up to 100 eV. It .is suggested that the pseudopotentials aptly mimic the effects of intrashell electron-electron correlations in the photoionization process. CHAPTER THREE: The extended Huckel theory is applied to the nitrogen trap in GaAs and GaP. Perfect crystal band structures are computed and are shown to be in reasonable agreement with those computed with empirical pseudopotentials. Nitrogen impurity levels in GaAs and GaP are computed using an extended Huckel cluster model. In each case the model pre-diets two states within the band gap, in contrast to experiment which detects one impurity state in GaP and none in GaAs. It is suggested that the choice of cluster used unrealistically concentrates states near the conduction band edge on the central atom.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Miller, Donald Lynn

Contributors dc:contributor

• Dow, J.D.

• KLL Auger transition
• atomic pseudopotentials
• Huckel theory
• electronic structure of matter

Statement dc:rights

• 1979 Donald Lynn Miller

Language dc:language

en

Identifier

358272

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25571