The adsorption state of thiophene on Au(111) formed with the immersion method was investigated by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS). The S 2p XPS spectra indicate that the thiolate, not thiophene, is adsorbed on the Au surface with the Au-S bond. The results of C K-edge NEXAFS reveal that the adsorbed species on Au(111) are mainly saturated hydrocarbons. This is in clear contrast with the vacuum-deposited thiophene on Au(111), in which thiophene is molecularly adsorbed on the surface. (c) 2005 Elsevier B.V. All rights reserved.