Investigations of the dynamics and growth of insulator films by high resolution helium atom scattering. Final report, May 1, 1985--April 30, 1997

Over the twelve years of this grant from the U.S. Department of Energy, DE-FG05-85ER45208, the over-reaching aims of this work have been to explore and to attempt to understand the fundamental physics and chemistry of surfaces and interfaces. The instrument we have employed m in this work is high-resolution helium atom scattering (HAS) which we have become even more convinced is an exceptionally powerful and useful tool for surface science. One can follow the evolution of the development and progress of the experiments that we have carried out by the evolution of the proposal titles for each of the four three-year periods. At first, m in 1985-1988, the main objective of this grant was to construct the HAS instrument so that we could begin work on the surface vibrational dynamics of crystalline materials; the title was {open_quotes}Helium Atom-Surface Scattering Apparatus for Studies of Crystalline Surface Dynamics{close_quotes}. Then, as we became more interested m in the growth of films and interfaces the title m in 1988-1991 became {open_quotes}Helium Atom Surface Spectroscopy: Surface Lattice Dynamics of Insulators, Metal and Metal Overlayers{close_quotes}. In 1991-1994, we headed even more m in this direction, and also recognized that we should focus more on insulator materials as very few techniques other than helium atom scattering could be applied to insulators without causing surface damage. Thus, the proposal title became {open_quotes}Helium Atom-Surface Scattering: Surface Dynamics of Insulators, Overlayers and Crystal Growth{close_quotes}. M in the final period of this grant the title ended up {open_quotes}Investigations of the Dynamics and Growth of Insulator Films by High Resolution Helium Atom Scattering{close_quotes} m in 1994-1997. The list of accomplishments briefly discussed in this report are: tests of the shell model; multiphoton scattering; physisorbed monolayer films; other surface phase transitions; and surface magnetic effects