Electronic States of Adsorbates, Clean Solid Surfaces and Bulk A-15 Compounds.

A self-consistent pseudopotential technique is used to study various surface systems. Calculated results are compared with photoemission experiments. Electronic states associated with the presence of steps on surfaces are investigated by considering a model structure of the Si(111) surface containing steps. A method to the problems of hydrogen and chlorine chemisorption on the Si(111) surface was then applied. Using a non-local ionic pseudopotential. The method was extended to calculate the electronic structure of bulk Nb and the ideal Nb(001) surface. A mixed basis approach was developed to allow more efficient calculation of electronic structures of transition metal surfaces and compounds. Using the mixed basis pseudopotential technique, realistic self-consistent calculations of the electronic structure of high temperature superconducting A-15 compounds Nb3Ge and Nb3Al were performed.