Structure and Dynamics of a Benzenedithiol Monolayer on a Au(111) Surface

Abstract

We use the universal force field (UFF) developed by Rappe et al. (Rappe, A. K.; Casewit, C. J.; Colwell, K. S.; Goddard, W. A.; Skiff, W. M. J. Am. Chem. Soc. 1992, 114, 10024) and the specific classical potentials developed from ab initio calculations for Au−benzenedithiol (BDT) molecule interaction to perform molecular dynamics (MD) simulations of a BDT monolayer on an extended Au(111) surface. The simulation system consists of 100 BDT molecules and three rigid Au layers in a simulation box that is rhombic in the plane of the Au surface. A multiple time scale algorithm, the double-reversible reference system propagator algorithm (double RESPA) based on the Nose−Hoover dynamics scheme, and the Ewald summation with a boundary correction term for the treatment of long-range electrostatic interactions in a 2-D slab have been incorporated into the simulation technique. We investigate the local bonding properties of Au−BDT contacts and molecular orientation distributions of BDT molecules. These results show t...