Fundamental research will be conducted on the structure of materials, especially structure at crystal surfaces. The primary theoretical tool will be realistic atomic-scale calculations carried out using a plane-wave pseudopotential approach to the local density approximation density-functional theory. The recent successful development of a new pseudopotential approach allows for the efficient application of these methods to systems containing first-row and transition-metal atoms. Both "static" total energy and structural refinement calculations, and finite temperature ab- initio molecular dynamics calculations, will be done. As in the past, a primary emphasis will be on structure at crystal surfaces, especially semiconductor surfaces. Previous calculations of surface stress and studies of elastic properties at surfaces and surface defects will be extended, with special emphasis on complex stress-induced surface structure and on elastic interactions between surface defects such as steps. New work will be done on oxides of silicon, tungsten, silver and gold. This involves study of bulk liquid and solid structure using ab-initio molecular dynamics, as well as study of oxygen at semiconductor, metal and metal-oxide surfaces.
