First principle simulation of STM images of benzene molecules adsorbed on a rhodium surface

Abstract STM images of Rh(111)-(3 × 3)-(C 6 H 6 +2CO) are simulated by the first principle local density approximation (LDA) method and the tunneling Hamiltonian formalism. Our simulation reproduces well the experimentally obtained STM images at both high and low bias voltage. The bias dependence of the STM images can be explained by the interaction between the π orbitals of benzene molecules and the rhodium atoms. Our simulation also shows that the π orbitals of benzene shift to higher binding energy while the σ orbitals remain unchanged, which is in good agreement with experiment.