The structure of a coronene adlayer formed in a benzene solution: studies by in situ STM and ex situ LEED

In situ scanning tunneling microscopy (STM) revealed that a highly ordered adlayer of coronene was formed on an Au(111) substrate by immersion in benzene solution containing coronene. High-resolution STM images allowed us to determine the packing arrangement of coronene. The coronene adlayer on Au(111)-(1×1) revealed a commensurate (4×4) symmetry (θ=0.0625) with a flat-lying orientation at 0.75 V versus the reversible hydrogen electrode (RHE) in aqueous HClO4. The adlayer structure of coronene determined by ex situ low-energy electron diffraction (LEED) using an ultrahigh vacuum-electrochemical (UHV-EC) technique was consistent with that determined by in situ STM in aqueous HClO4.