NEUTRON SCATTERING INVESTIGATIONS OF THE DYNAMICS OF THIN FILMS ADSORBED ON SOLID SURFACES. J. Z. Larese, Chemistry Dept., Brookhaven National Laboratory, Upton, NY 11973, USA

High-resolution inelastic and quasielastic neutron scattering (INS) techniques are ideal probes of the dynamical properties of films adsorbed on solid surfaces. When these dynamical measurements are combined with data from structural, thermodynamic and computer simulation studies it is often possible to develop a rather complete picture of the microscopic properties of an adsorbed film system. In order to illustrate the power of INS techniques we will discuss several prototypical examples. In particular, the continuous melting of monolayer ethylene and the layer-by-layer melting of multilayer argon films on the basal plane of graphite and the rotational tunneling of methane films on the (100) surface of MgO. Some indication of how these studies might be used in the investigation of surface mediated chemical reactions will also be provided. This research was performed under the auspices of the U.S. Dept. of Energy, Material Science Division, under Contract # DE-AC02-76CH00016.