Hiroshi Kato

On the Unrestricted Hartree–Fock Wavefunction

The unrestricted Hartree–Fock (UHF) wavefunction is analyzed and interpreted in configuration‐interaction (CI) language. The results of the present study are as follows. (i) The UHF wavefunction includes only one type of the singly excited configurations [Eq. (20)], and thus the correlation effects included are very limited ones, compared with the usual CI treatment. (ii) The weight of the lowest contaminating spin function, included in the UHF wavefunction, decreases with increasing spin multiplicity. (iii) The annihilation of the lowest contaminating spin function little affects the electron density distributions and other physical quantities, the operators of which commute with the annihilation operator. (iv) In the UHF method, the “spin‐appearing” (spin‐polarization and spin‐delocalization) mechanisms are clearly divided, and an approximate method to separate these contributions is generalized, and some discussions about spin annihilation are made.

Molecular cloning of cDNAs for human fibroblast nucleotide pyrophosphatase.

Nucleotide pyrophosphatase (NPPase) activity is markedly elevated in cultured skin fibroblasts from patients of Lowes syndrome. cDNA clones encoding the NPPase were isolated using synthetic oligonucleotide probes designed on the basis of partial amino acid sequence of the enzyme purified from human placenta. The complete sequences of these clones yielded a merged sequence of 3508 bases. The polypeptide chain of the enzyme was deduced to comprise 873 amino acids with a calculated molecular weight of 99,703 and had the characteristics of a class II transmembrane protein. Ten potential N-glycosylation sites were detected in the protein. RNA blot analysis showed that human fibroblasts contain two minor mRNAs of 7.0 and 8.2 kb, respectively, in addition to a major 3.6-kb species that coincides with the merged cDNA in size. A computer search of a nucleotide sequence data-base revealed that plasma cell membrane glycoprotein PC-1, whose function was unknown at the time, is identical with the NPPase. Comparison of the amino acid sequence of the NPPase with the active site sequence of bovine 5-nucleotide phosphodiesterase allowed the assignment of a putative active site domain to the central region of the COOH-terminal extracellular domain of the NPPase. The gene for human NPPase was localized to chromosome 6 at q22-q23 by in situ hybridization with a fragment of the NPPase cDNA.

Theoretical studies of hydrogen molecule adsorption on flat and stepped platinum surfaces

Abstract Theoretical calculations have been applied to the adsorption of hydrogen molecule on flat and stepped platinum surfaces. The method of large unit cell is modified to deal with the stepped surface as well as the flat one. This method is free from the boundary effect which is inevitable in the cluster method. The results calculated for the d-band width and the highest occupied level are in good agreement with the experiments. For the dissociative adsorption, the bottom of the step site is the most favorable, and the result is attributed to the extra orbital interactions at this site.

Semi-empirical molecular orbital calculations the electronic structure and the spin-orbit coupling in azabenzenes

AbstractElectronic structures of pyridine, pyrazine, pyrimidine and pyridazine are studied by a semiempirical SCF method for valence electron systems previously proposed by the present authors. The charge distributions, transition energies and oscillator strengths of these compounds are calculated. The calculated results show fairly good agreement with the observed ones. Using these results, we have further calculated the oscillator strengths of singlet-triplet transitions n

Novel Perturbation Theory in Simple LCAO Treatment of Conjugated Molecules—Method of Perturbed Secular Determinant

(f_{T_1 to S_0 } )

Spin polarization and spin delocalization in unrestricted hartree-fock method

n and the life times of the triplet states (τ). In this treatment, we have considered the mixing of various singlets with T1 and triplets with S0, and the effect of σ-electrons is studied.ZusammenfassungEs werden nach einer von den Autoren dieser Arbeit vorgeschlagenen Methode die Elektronenstrukturen von Pyridin, Pyrazin, Pyrimidin und Pyridazin studiert. Die halbempirische SCF-Methode für Valenzelektronensysteme gestattet die Berechnung der Ladungsverteilungen, Übergangsenergien und Oszillatorstärken, die in recht guter Übereinstimmung mit der Beobachtung stehen. Ferner werden die Oszillatorstärken von Singulett-Triplett-Übergängen n

ELS study on chemisorbed state of CO on Cr(110)

(f_{T_1 to S_0 } )