We studied the adsorption state of dimethyl disulfide and methylthiolate on the Au(111) surface by means of the density functional theory (DFT) within a generalized gradient approximation and experimental high-resolution electron energy loss spectroscopy (HREELS) techniques. It turns out that the methylthiolate adsorption is more stable than the dimethyl disulfide adsorption and that the most stable adsorption site for the methylthiolate is the bridge site slightly off-centered towards the fcc-hollow site with its S–C bond tilted from the surface normal by 53°. HREELS results are in excellent agreement with the DFT results, providing very strong support to the depicted adsorption scenario.

The adsorption and desorption of n-alkanethiol monolayers on Au(111) have been studied under ultrahigh-vacuum condition by the use of scanning tunneling microscopy (STM), thermal desorption spectroscopy (TDS), and Auger electron spectroscopy (AES). Molecularly resolved STM observations for the alkanethiol monolayers have revealed that at least four different phases evolve during growth, which results in a multistep growth of the monolayer. The desorption species drastically changes at a critical coverage, which is accompanied by a structure change from a low-density flat-lying phase to a denser standing-up phase: While the latter phase bimolecularly desorbs as disulfides, the former phase unimolecularly desorbs as thiolate radicals. The coverage-dependent change of the desorption mode is explained in terms of the difference in the molecule-substrate bonding.

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Surface structures of rutile TiO(2) (011) are determined by a combination of noncontact atomic force microscopy (NC-AFM), scanning tunneling microscopy (STM), and density functional calculations. The surface exhibits rowlike (n x 1) structures running along the [01] direction. Microfaceting missing-row structural models can explain the experimental results very well. Calculated images for NC-AFM and STM are in good agreement with the experimental results. A decrease of the density of dangling bonds stabilizes the surface energy, which results in the microfaceting missing-row reconstructions.

The coverage dependence of desorption behavior of n-alkanethiol monolayers on Au(111) has been studied using thermal desorption spectroscopy (TDS) together with scanning tunneling microscopy (STM) to investigate the molecule−substrate interactions. STM observations indicated four different phases during the growth. We present for the first time evidence for a drastic coverage-dependent change of desorption species, which is parallel with a structure change from a low-density phase to a denser phase:  while the thiolates in the latter phase bimolecularly desorb as disulfides, those in the former phase unimolecularly desorb as thiolate radicals.

Atomic and electronic structures of the SrTiO3(100)-(square root of 5 x square root of 5) - R26.6 degrees surface are studied by using scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NC-AFM). Instead of the well established oxygen vacancy model, it is found that a structural model, consisting of an ordered Sr adatom at the oxygen fourfold site of a TiO2 terminated layer, can explain the experimental results very well. We theoretically simulate the model cluster with the first-principles total-energy calculation. Calculated density of states and images for STM and NC-AFM are in good agreement with the experimental results.

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