A combined low-energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS) study on the structural properties of heptanethiol (C7H15SH) monolayers prepared by either adsorption from the liquid or chemical vapor deposition (CVD) on Au(111) single crystal surfaces has been performed. Deposition from the vapor produces a commensurate c(17×√3) superstructure which exhibits a well-defined LEED pattern. XPS data recorded for these films reveal that the hydrocarbon molecules are orientated with their axes parallel to the substrate surface. Compared to the more commonly used fabrication of alkanethiolate self-assembled films by adsorption from solution the c(17×√3) CVD film exhibits a coverage of less than 40%.

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High-resolution inelastic He-atom surface scattering experiments have been carried out on an in situ cleaved NaCl͑001͒ crystal surface for the incident wave-vector range of 4.29-6.07 Å Ϫ1 in the ͗110͘ high-symmetry direction to detect the recently predicted effect, the focused inelastic resonance ͑FIR͒. The scattering angle for the resonance in the ͗110͘ direction is uniquely predicted based on the reciprocal lattice vector exchanged in the process for the bound state ͉⑀ 1 ͉ϭ3.4Ϯ0.1 meV. This value is slightly lower than the 3.7Ϯ0.4 meV value found in the literature. The convincing evidence for the FIR effect comes from a systematic analysis of the angular distributions in combination with an energy analysis based on time-of-flight spectra.