AB-INITIO CALCULATIONS OF THE GOLD-SULFUR INTERACTION FOR ALKANETHIOLMONOLAYERS

We have performed ab-initio geometry optimization of SCH3 absorbed on cluster models of Au(111), to examine the gold-sulfur-carbon head grou p energetics for self-assembled monolayers of alkanethiols on gold. Th e ab-initio calculations are performed using gradient-corrected densit y functional theory. The data obtained from these calculations, are us ed to construct a realistic empirical potential function to describe t he complete headgroup-Au(111) energy surface. In particular, the depen dence of the energy of the system on the Au surface-sulfur separation, and the surface-sulfur-carbon angle is determined for positions repre sentative of the entire gold(111) surface plane.