Simulation of scanning tunneling microscope image of benzene chemisorbed on a Pd(111) electrode surface by density functional theory

Alnald Javier,¹ Ding Li,¹ Perla B Balbuena,² Manuel P Soriaga<sup>1

1</sup>Department of Chemistry, Texas A&M University, College Station, TX, USA; ²Department of Chemical Engineering, Texas A&M University, College Station, TX, USA

Abstract: A computational method based on density functional theory was used to simulate the scanning tunneling microscopy (STM) images of benzene chemisorbed on a Pd(111) electrode in order to confirm the adsorption site of the aromatic molecule on the metal surface held at a certain applied potential. The simulated STM images on various adsorption sites were obtained and compared with the experimental electrochemical STM images. The simulation results indicate that when the potential of the Pd electrode is held at 0.3 V, benzene is chemisorbed on a threefold hollow site; at 0.55 V, the molecule is adsorbed on a position between a threefold and a twofold bridge site. These findings corroborate previously published experimental electrochemical STM results.

Keywords: STM simulation, benzene chemisorption, Pd(111) surface, potential-dependent adsorbate reconstruction, electrochemical compact layer