Biomedical subjects

Ryo Hirayama

Publications and source records attributed to Ryo Hirayama.

3 recordsLinked to original sources

PubMed2006

Inner-valence states of N2+ and the dissociation dynamics studied by threshold photoelectron spectroscopy and configuration interaction calculation.

The N2(+) states lying in the ionization region of 26-45 eV and the dissociation dynamics are investigated by high-resolution threshold photoelectron spectroscopy and threshold photoelectron-photoion coincidence spectroscopy. The threshold photoelectron spectrum exhibits several broad bands as well as sharp peaks. The band features are assigned to the N2(+) states associated with the removal of an inner-valence electron, by a comparison with a configuration interaction calculation. In contrast, most of the sharp peaks on the threshold photoelectron spectrum are allocated to ionic Rydberg states converging to N2(2+). Dissociation products formed from the inner-valence N2(+) states are determined by threshold photoelectron-photoion coincidence spectroscopy. The dissociation dynamics of the inner-valence ionic states is discussed with reference to the potential energy curves calculated.

Journal Article↗

PubMed2005

Compact and efficient basis sets of s- and p-block elements for model core potential method.

We propose compact and efficient valence-function sets for s- and p-block elements from Li to Rn to appropriately describe valence correlation in model core potential (MCP) calculations. The basis sets are generated by a combination of split MCP valence orbitals and correlating contracted Gaussian-type functions in a segmented form. We provide three types of basis sets. They are referred to as MCP-dzp, MCP-tzp, and MCP-qzp, since they have the quality comparable with all-electron correlation consistent basis sets, cc-pVDZ, cc-pVTZ, and cc-pVQZ, respectively, for lighter atoms. MCP calculations with the present basis sets give atomic correlation energies in good agreement with all-electron calculations. The present MCP basis sets systematically improve physical properties in atomic and molecular systems in a series of MCP-dzp, MCP-tzp, and MCP-qzp. Ionization potentials and electron affinities of halogen atoms as well as molecular spectroscopic constants calculated by the best MCP set are in good agreement with experimental values.

Journal Article↗

PubMed2004

Nonadiabatic transition in the dissociation process from inner valence states of O(2) (+).

In a previous paper we reported a study of the electronic structures of inner valence states of O(2) (+) and the dissociation process, where there remained some questions as to the origins of the dissociation fragment formation of the O+((2)D)+O((3)P) limit in observed spectra. In this paper, we present the results of calculations of the nonadiabatic transition probabilities of the multichannel dissociation process from the inner valence states of O(2) (+) and reproduce the general features of observed spectra previously reported, including fragment formation, using the Zhu-Nakamura theory.

Letter↗