Ab initio molecular orbital model of scanning tunneling microscopy. Benzene and benzene adsorbed on a Ag surface

The molecular orbital (MO) model of scanning tunneling microscopy (STM) developed previously is applied to the Pd2 tip C6H6 sample system to examine the effect of tilting the tip, and to benzene adsorbed on a silver surface to investigate the effect of the surface-adsorbate interaction on the STM image. The effect of tilting the tip is shown to depend on the nature of the tip MOs responsible for the STM current. The possibility of elucidating the site and geometry of the adsorbate by a combined use of experimental and theoretical STM images is discussed.