The surface science techniques of Auger electron spectroscopy, low energy electron diffraction, ultraviolet photoelectron spectroscopy, alkali ion scattering spectroscopy and forward focusing angle-resolved X-ray photoelectron spectroscopy will be used to examine ultrathin films and monolayers. The systems to be studied include palladium films. Studies will be carried out of the effect of various gases, including carbon monoxide, nitric oxide, nitrogen dioxide, ethylene and acetylene, on the film properties using primarily high resolution electron energy loss spectroscopy and temperature programmed desorption. Kinetic studies will be performed and some catalytic reactions will be examined. The analytical probes used have the ability to probe subtle changes in the geometric and electronic structure of the materials studied, and should enable a better understanding of chemisorption and reactivity to be obtained. %%% The research, in the general area of Analytical and Surface Chemistry, focuses on surface science studies of monolayers and ultrathin films of palladium on early transition metal single crystal substrates. The study aims to correlate these studies with the chemisorption and reaction properties of the films. The work promises to lead to a greater understanding of the properties of thin metal films which will have a wide range of important applications in materials science and catalysis.