Yoshitada Morikawa

Bio: Yoshitada Morikawa is an academic researcher from Osaka University. The author has contributed to research in topics: Density functional theory & Adsorption. The author has an hindex of 44, co-authored 216 publications receiving 6826 citations. Previous affiliations of Yoshitada Morikawa include Kyoto University & University of Tokyo.

CO Chemisorption at Metal Surfaces and Overlayers

Abstract: A database of ab initio calculations of the chemisorption energy of CO over Ni(111), Cu(111), Ru(0001), Pd(111), Ag(111), Pt(111), Au(111), $\mathrm{Cu}{}_{3}$Pt(111), and some metallic overlayer structures is presented. The trends can be reproduced with a simple model describing the interaction between the metal $d$ states and the CO $2{\ensuremath{\pi}}^{*}$ and 5 $\ensuremath{\sigma}$ states, renormalized by the metal $\mathrm{sp}$ continuum. Our model rationalizes the results by Rodriguez and Goodman [Science 257, 897 (1992)] showing a strong correlation between the CO chemisorption energy and the surface core level shift.

Adsorption state of dimethyl disulfide on Au(111): Evidence for adsorption as thiolate at the bridge site

Abstract: 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.

Spin- and energy-dependent tunneling through a single molecule with intramolecular spatial resolution.

Abstract: We investigate the spin- and energy-dependent tunneling through a single organic molecule (CoPc) adsorbed on a ferromagnetic Fe thin film, spatially resolved by low-temperature spin-polarized scanning tunneling microscopy. Interestingly, the metal ion as well as the organic ligand show a significant spin dependence of tunneling current flow. State-of-the-art ab initio calculations including also van der Waals interactions reveal a strong hybridization of molecular orbitals and substrate $3d$ states. The molecule is anionic due to a transfer of one electron, resulting in a nonmagnetic ($S=0$) state. Nevertheless, tunneling through the molecule exhibits a pronounced spin dependence due to spin-split molecule-surface hybrid states.

Theoretical study of n-alkane adsorption on metal surfaces

Abstract: 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 distance between the molecule and the substrate.

Towards the computational design of solid catalysts

Abstract: Over the past decade the theoretical description of surface reactions has undergone a radical development. Advances in density functional theory mean it is now possible to describe catalytic reactions at surfaces with the detail and accuracy required for computational results to compare favourably with experiments. Theoretical methods can be used to describe surface chemical reactions in detail and to understand variations in catalytic activity from one catalyst to another. Here, we review the first steps towards using computational methods to design new catalysts. Examples include screening for catalysts with increased activity and catalysts with improved selectivity. We discuss how, in the future, such methods may be used to engineer the electronic structure of the active surface by changing its composition and structure.

How copper catalyzes the electroreduction of carbon dioxide into hydrocarbon fuels

Abstract: Density functional theory calculations explain copper's unique ability to convert CO2 into hydrocarbons, which may open up (photo-)electrochemical routes to fuels.

Maximally-localized Wannier Functions: Theory and Applications

Abstract: The electronic ground state of a periodic system is usually described in terms of extended Bloch orbitals, but an alternative representation in terms of localized "Wannier functions" was introduced by Gregory Wannier in 1937. The connection between the Bloch and Wannier representations is realized by families of transformations in a continuous space of unitary matrices, carrying a large degree of arbitrariness. Since 1997, methods have been developed that allow one to iteratively transform the extended Bloch orbitals of a first-principles calculation into a unique set of maximally localized Wannier functions, accomplishing the solid-state equivalent of constructing localized molecular orbitals, or "Boys orbitals" as previously known from the chemistry literature. These developments are reviewed here, and a survey of the applications of these methods is presented. This latter includes a description of their use in analyzing the nature of chemical bonding, or as a local probe of phenomena related to electric polarization and orbital magnetization. Wannier interpolation schemes are also reviewed, by which quantities computed on a coarse reciprocal-space mesh can be used to interpolate onto much finer meshes at low cost, and applications in which Wannier functions are used as efficient basis functions are discussed. Finally the construction and use of Wannier functions outside the context of electronic-structure theory is presented, for cases that include phonon excitations, photonic crystals, and cold-atom optical lattices.