Surface Chemical Reaction Enhanced by Adsorbate-Electron Interaction

Abstract

We have observed two type of bonding configuration of Iodobenzene (C6H5I) molecule upon room temperature adsorption on the Si (111) -7×7 surface and investigated an effect of Adsorbate-Electron interaction on a bonding configuration change of the Iodobenzene molecules on the Si(111)-7×7 surface using scanning tunneling microscope (STM). With the direct-current heating, a conversion rate of the bonding configuration as a function of the lattice temperature, K(Tl), has been determined. The plot of ln(K(T)) vs. T shows a deviation from a Arrhenius straight line, which suggests that the current accelerates the molecule's reaction by heating the adsorbate preferentially above the lattice temperature. Though tunneling current induced chemical reaction has been reported, we believe this is the first report of a direct observation that the interaction between an adsorbate and lattice current causes a chemical reaction.