Yoshitada Morikawa

The interaction between n-alkane and metal surfaces has been studied by means of density-functional theoretical calculations within a generalized gradient approximation (GGA). We demonstrate that although the GGA cannot reproduce the physisorption energy well, our calculations can reproduce the experimentally observed work-function change and softening of the CH stretching mode reasonably well. We also show that the most significant factor determining their dependence on metal substrates is the

Adsorption geometries and vibrational modes of ${\mathrm{C}}_{2}{\mathrm{H}}_{2}$ on the Si(001) surface are studied by means of density-functional theory within the generalized gradient approximation. By comparing theoretically calculated high-resolution electron-energy-loss spectra with experimentally reported spectra, it is clearly shown that at least two energetically most stable adsorption states coexist.

We have studied oxygen and potassium coadsorption on the Si(001) surface with first-principles molecular dynamics. The present calculation gives a strong support to the structural model based on double-layer K adsorption. Oxygen adsorption on the K/Si(001) surface reduces the work function by 0.7 eV and activates the negative electron affinity in accord with experimental results. The oxygen atoms are adsorbed slightly below the potassium atoms and accumulate a valence charge around the surface r

We have studied the dehydration process of formic acid on a TiO2(110) surface by using first-principles theoretical calculations. Formic acid dissociatively adsorbs to form formate and hydroxyl. It turns out that simple decomposition processes of the formate on the stoichiometric surface are energetically unfavorable. The formation of H2O and O vacancies from two neighboring bridging hydroxyls is relatively easy and the activation barrier is calculated to be 114 kJ/mol. On the TiO2(110) surface