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141.
Toshikatsu Koga 《Theoretical chemistry accounts》2002,107(4):246-249
On the basis of multiconfiguration Hartree–Fock calculations, correlated electron-pair intracule (relative motion) and extracule
(center-of-mass motion) properties are reported for the Li atom in momentum space. The present results are more accurate and
consistent than those in the literature.
Received: 10 September 2001 / Accepted: 11 December 2001 / Published online: 22 March 2002 相似文献
142.
Kuniaki Takata Koshi Kusumoto Toshikatsu Sata Yukio Mizutani 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):645-659
Studies of the copolymerization of chloromethylstyrene (CMS) and divinylbenzene (DVB) were done in the presence or absence of poly-(vinyl chloride) (PVC) in order to prepare anion-exchange membranes of excellent performance by the paste method. The copolymerization rate decreases when PVC is added and increases when the DVB quantity is increased in the presence of PVC. The copolymerization rate of the isomers of CMS and DVB increases in the following order: p-DVB > m-DVB > p-ethylvinylbenzene > p-CMS > m-CMS ≈ m-ethylvinylbenzene. This order is not affected by the presence of PVC. The copolymerization of CMS and DVB takes place partially in PVC particles. 相似文献
143.
Beatriz Miguel Toshikatsu Koga José M. García de la Vega 《Theoretical chemistry accounts》2000,104(2):167-171
Double- and triple-zeta basis sets of Slater-type functions (STFs) are developed for the 17 atoms from He to Ar. For computational
economy, the exponents of STFs corresponding to the same atomic subshell are restricted to be common. Instead, the principal
quantum numbers of the STFs are thoroughly optimized within the framework of integer values to reduce the energy loss due
to the common exponent restriction.
Received: 10 November 1999 / Accepted: 25 January 2000 / Published online: 19 April 2000 相似文献
144.
Toshikatsu Sata Yoriko Yamane Koji Matsusaki 《Journal of polymer science. Part A, Polymer chemistry》1998,36(1):49-58
Anion exchange membranes with pyridinum groups and various pyridinium derivative groups were prepared from a copolymer membrane composed of chloromethylstyrene and divinylbenzene, and pyridine and pyridine derivatives. The anion exchange membranes obtained showed excellent electrochemical properties in electrodialysis. The transport numbers of sulfate ions, bromide ions, nitrate ions, and fluoride ions relative to chloride ions were evaluated in connection with the species of a substituent and the position of the substituent in the pyridinium groups. In general, when a hydrophilic substituent (methanol groups) existed at the 2-position of the pyridinium groups, nitrate ions and bromide ions, which are less hydrated, permeated through the membranes with difficulty, and sulfate ions permeated selectively through the membranes. On the other hand, when hydrophobic groups, for example, ethyl groups, existed at the 2-position of the pyridinium groups, bromide ions and nitrate ionspermeated selectively through the membranes and fluoride ions had difficulty permeating through the membranes. The carbon number of the alkyl chain of 4-alkyl pyridinium groups also affected permeation of nitrate ions and bromide ions due to the change in hydrophilicity of the membranes. Though the hydration of the anions and the species of the substituent at the 2-position of the pyridinium groups were related to selective permeation of the anion through the membranes, permeation of sulfate ions was not as sensitive to the hydrophilicity of the membranes. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 49–58, 1998 相似文献
145.
E. Romera J. S. Dehesa Toshikatsu Koga 《International journal of quantum chemistry》1997,61(3):525-531
An analytical expression of the electron density function p(r) due to Schwartz for two-electron atomic systems is applied to a detailed study of density-dependent properties of relatively heavy two-electron ions. Comparison of the Schwartz results with those from accurate Hartree-Fock and Hylleraas wave functions shows that despite its simple yet analytical form, the Schwartz density has a quantitative applicability in the density study of two-electron atoms within the nonrelativistic framework. © 1997 John Wiley & Sons, Inc. 相似文献
146.
A relativistic virial theorem is derived for atoms in a general manner. The virial ratio consists of the usual V/T term and a correction term W/T, where T, V, and W are the kinetic energy, the potential energy, and correction terms, respectively. Explicit forms of W are presented for four specific nuclear potential models. Numerical calculations for a uniform nuclear charge model show
that the magnitude of the correction term W/T increases with increasing atomic numbers and that it modifies the ratio V/T considerably for atoms with large atomic numbers in particular.
Received: 21 November 2000 / Accepted: 8 January 2001 / Published online: 3 April 2001 相似文献
147.
Eduardo V. Ludea Roberto Lpez-boada Jorge E. Maldonado Elmer Valderrama Eugene S. Kryachko Toshikatsu Koga Juergen Hinze 《International journal of quantum chemistry》1995,56(4):285-301
The local-scaling transformation version of density functional theory (LS-DFT ) is reviewed. It is shown that in the context of LS-DFT it is possible to construct N-representable energy density functionals and that the theory provides systematic ways for calculating strict upper bounds to the exact energies. The importance of the concept of “orbit” in LS-DFT is indicated and several approaches leading to intraorbit and interorbit optimization are discussed. Results of the application of these optimization procedures to the determination of upper bounds for the ground-state energy of the beryllium atom are given. Also, numerical results are reported on the use of local scaling transformations for the direct solution of the Kohn-Sham equations via the density-constrained minimization of the kinetic energy of a noninteracting system. © 1995 John Wiley & Sons, Inc. 相似文献
148.
149.
The Pummerer rearrangement of 1-deoxy-5-thioglucopyranose derivatives carrying acetonides at the C3,4-positions proceeded regioselectively at the C1 position by treating with TFAA in the presence of pyridine. Studies employing deuterium-labelled derivatives revealed that the reaction was induced by E2 1,2-elimination of trifluoroacetic acid of the trifluoroacetoxy sulfonium intermediate. This methodology was applied to the synthesis of an isomaltotriose derivative consisting of 5-thioglucopyranoside units. 相似文献