Under this National Science Foundation Young Investigator Award, Thomas J. Curtiss will explore the chemical dynamics of gas/surface collisions. High purity, high intensity neutral radical beams (for example, OH or CFx where x is 1, 2, or 3) are generated using electric field focussing methods. Charge transfer interaction mechanisms are investigated using state-selective laser detection methods to probe vibrational state populations of inelastically and reactively scattered products. %%% The chemistry of gas phase atoms and radicals with semiconductor and metal surfaces is central to modern processing methods of thin films, namely plasma activated etching and plasma activated chemical vapor deposition. This is particularly true in the microelectronics and coatings industries. To date, optimization of thin film processing methods has been done empirically, by adjusting feedgas composition, pressure and temperature. This study is an attempt to study the surface chemistry more systematically.