Yasuyuki Ishikawa
Professor
Contact
Office: FB 319 – located on the third floor of Facundo Bueso Bldg
Email: yishikawa@uprrp.edu
Phone: 787-764-0000 ext. 5908
Education
Ph.D., University of Iowa, 1976.
Postdoctoral Fellow, Rutgers University, 1976-78.
Wissenschaftlicher Mitarbeiter, Universität Siegen, Germany, 1978-80.
Research Interests
Relativistic Many-Body Theory; Ab Initio Monte Carlo/Molecular Dynamics Simulation of Many-Body Systems; Theoretical modeling and simulation of electrochemical systems
Research Focus
Relativistic many-body theory for atoms and molecules: Heavy atom species are many-electron systems with complicated state structures which push conventional computational techniques to their limits. During the last two decades, we have been trying to find suitable fully relativistic SCF and many-body theories (e.g., relativistic many-body perturbation theory and relativistic coupled cluster theory) for atoms and molecules as a means of turning physical pictures of electronic systems in which relativistic and QED effects are not negligible into ab initio computational tools, and of extracting from the Dirac relativistic electron theory more nearly correct physical pictures.
Ab initio Monte Carlo/molecular dynamics studies of structure and dynamics of polyatomic systems and solid/liquid interface: The major difficulty in computer simulations of the structure and dynamics of metal, semiconductor and molecular clusters is the description of the many-body interactions. The pair-wise approximation commonly used to describe these systems does not work well for covalent and metallic systems where many-body interactions play a crucial role. We have developed ab initio molecular dynamics and replica Monte Carlo algorithms that describe the many-body interactions in these clusters in terms of ab initio correlated method.
Selected Recent Publications
Relativistic multireference many-body perturbation theory calculations: benchmanks
on Zn-like ions, M. J. Vilkas and Y. Ishikawa, Phys. Rev. A 72 (2005) 032512.
Atomic transition energies and the variation of the fine-structure constant α, A. Borschevsky, E. Eliav, Y. Ishikawa, and U. Kaldor, Phys. Rev. A 74 (2006) 062504.
Relativistic R-matrix close-coupling method based on the effective Hamiltonian in many-body perturbation theory, M. J. Vilkas and Y. Ishikawa, Phys. Rev. A 75 (2007) 062508.
Direct molecular dynamics and density-functional theoretical study of electrochemical hydrogen oxidation reaction and underpotential deposition of H on Pt(111), Y. Ishikawa, J. J. Mateo, D. A. Tryk, C. R. Cabrera, J. of Electroanal. Chem. 607 (2007) 37.
A combined MD/DFT study on the structures and electronic properties of hydrating water molecules in the minor groove of a decameric DNA duplex, T. Tsukamoto, Y. Ishikawa, T. Natsume, K. Dedachi, and N. Kurita, Chem. Phys. Letters, 441 (2007) 136.
A Fock space coupled cluster study on the electronic structure of the UO2, UO2+, U4+, and U5+ species , Ivan Infante, Ephraim Eliav, Marius J. Vilkas, Yasuyuki Ishikawa, Uzi Kaldor, and Lucas Visscher, J. Chem. Phys. 126 (2007) 184305.
A relativistic R-matrix close-coupling method based on the effective many-body Hamiltonian: Benchmarks on the electron-impact excitations of Kr6+ ion, Y. Ishikawa and M. J. Vilkas, Phys. Rev. A 77 (2008) 052701.
Underpotential deposition of hydrogen on Pt(111): A combined direct molecular
dynamics/density-functional theoretical study, J. J. Mateo, D. A. Tryk, C. R. Cabrera, and Y. Ishikawa, Molecular Simulation (2008) in press.