Electric Field Effect on the Adsorption State of Methylthiolate on Au(111)

Abstract

We have studied the effect of the electric field on the adsorption structures of methylthiolate(MeS) on the Au(111) surface by using density functional theory. MeS has the bridge, fcc-hollow and ontop adsorption configurations and the relative stability among those configurations can be changed by applying the electric field perpendicular to the surface. The energy difference between the bridge and fcc-hollow configurations can be well described by a simple dipole-field interaction model and the relative stability is reversed at an electric field of about 26 V/nm. As for the energy difference between the bridge and ontop configurations, the effect of polarization becomes large at strong electric field.