Eisaku Miyoshi

Kyushu University, Hukuoka, Fukuoka, Japan

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Publications (81)180.76 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To design half-metallic materials in thin film form for spintronic devices, the electronic structures of full Heusler alloys (Mn2FeSi, Fe2MnSi, Fe2FeSi, Fe2CoSi, and Co2FeSi) with an L21 structure have been investigated using density functional theory calculations with Gaussian-type functions in a periodic boundary condition. Considering the metal composition, layer thickness, and orbital symmetries, a 5-layered Co2FeSi thin film, whose surface consists of a Si layer, was found to have stable half-metallic nature with a band gap of ca. 0.6 eV in the minority spin state. Using the group theory, the difference between electronic structures in bulk and thin film conditions was discussed.
    Thin Solid Films 05/2012; 520(15):4979–4983. · 1.87 Impact Factor
  • Hirotoshi Mori, Kazumi Ishii, Eisaku Miyoshi
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    ABSTRACT: A photo-induced geometry isomerization reaction mechanism of a photochromic inorganic complex, [Cu(dieten)2]2+ (dieten = N,N′-diethyletylenediamine), was investigated with density functional molecular orbital theory calculations. A new stable cis-isomer that is assigned to a photo-irradiated (PI) phase was found. In the PI geometry, two N,N′-diethyl groups are placed more closely than in the most stable low-temperature (LT) phase, and the complex has a slightly twisted structure with steric hindrance. Recently, Takahashi et al. have suggested that two ethyl groups were in trans position in the PI phase from the EXAFS and XANES observation; however, no energy minimum corresponds to such a PI state was found. The photochromic reaction mechanism and electronic structure of [CuII(dieten)2]2+ are discussed from a theoretical point of view.
    Journal of Theoretical and Computational Chemistry 11/2011; 05(04). · 0.52 Impact Factor
  • Yoshiko Sakai, Eisaku Miyoshi, Tosinobu Anno
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    ABSTRACT: Multireference singly and doubly excited CI (MRSDCI) calculations are performed on the NaI molecule by using a model potential method. The potential energy curves of the ground and first excited 1∑+ states are generated over a wide range of internuclear distance R. The curves yield the avoided crossing, which is expected to arise by the mixing of the ionic and covalent configurations, and thus the curve of the first excited state shows a shallow minimum. The geometrical parameters, dipole moment, and dissociation energy are calculated. The agreement of those with the experimental results is satisfactory. Keywords: NaI, MRSDCI calculation, model potential method, potential curve, excited state.
    Canadian Journal of Chemistry 02/2011; 70(2):309-313. · 0.96 Impact Factor
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    ABSTRACT: Model potential parameters and valence orbitals were generated for the transition metal atoms Sc through Hg. They are named the spd-MPs and are supplementary to the sd-MPs presented in the preceding article. The outermost core np electrons were treated explicitly together with valence nd and (n + 1)s electrons, and the remaining electrons were replaced by a model potential. The model potential parameters and valence orbitals were determined in the same way as the sd-MPs. Major relativistic effects (via the mass velocity and Darwin terms) were also incorporated in the spd-MPs for the second-and third-row transition metal atoms. The results of numerical nonrelativistic Hartree-Fock (HF) calculations for the first-row transition metal atoms and of the quasirelativistic HF calculations with Cowan and Griffin's method for the second-row and third-row transition metal atoms were used as reference data in determination of the spd-MPs.
    Journal of Computational Chemistry 01/2011; 8(3):256 - 264. · 3.84 Impact Factor
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    ABSTRACT: Model potential parameters and valence orbitals were generated for the transition metal atoms Sc through Hg. Only the nd and (n + 1)s valence electrons were treated explicitly and the effects of the remaining electrons were replaced by model potentials. For brevity they may be called sd-MPs. Major relativistic effects were incorporated on the level of Cowan and Griffin's quasirelativistic Hartree-Fock (QRHF) method for the second and third transition metal atoms. The model potential parameters and valence orbitals were determined so as to reproduce the results of the numerical Hartree-Fock reference calculations. The obtained valence orbitals have inner nodal structure. The model potential method can yield a balanced description of the s2dn–1, sdn, and dn + 1 configurations of the atoms. The polarization functions were also generated for the use in molecular calculations.
    Journal of Computational Chemistry 01/2011; 8(3):226 - 255. · 3.84 Impact Factor
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    ABSTRACT: 4f-in-core large-core model core potentials (LC-MCP), in which the effects of open shell 4f electrons as well as those of other electrons up to 4d were replaced with MCPs, were developed for the lanthanide trivalent ions. In order to achieve desired accuracy, the LC-MCPs were calibrated using static quantum-chemical calculations for LnF3, and tested by ab initio molecular dynamics simulation on the hydration dynamics of La3+. Comparing calculated results using the 4f-in-core LC-MCPs with those employing 4f-in-valence MCPs, we found that the 4f-in-core LC-MCPs require less computational costs than the 4f-in-valence MCPs with keeping enough accuracy for describing chemical properties of trivalent lanthanide systems.Graphical abstractView high quality image (59K)Highlights► Development of 4f-in-core model core potentials (MCPs) for trivalent lanthanides. ► Comparison between 4f-in-core large core MCPs (LC-MCPs) and 4f-in-valence MCPs. ► Potential calibration study. ► Hydration dynamics of trivalent lanthanide ions.
    Chemical Physics Letters 01/2011; 510:261-266. · 2.15 Impact Factor
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    ABSTRACT: Molecules HRgF (Rg = Ar, Kr, Xe, Rn) were studied at levels of theory that included electron correlation, taking relativistic effects into account either by using the recently developed parametrization of the extended model core potentials and basis sets or by using the Douglas-Kroll method with all-electron basis sets. Charge distributions were calculated according to Mulliken, Lowdin, and natural bond orbital methods of population analysis and the results of these methods were compared, confirming that bonding in these molecules corresponds to interaction between the fluoride anion and the RgH(+) moiety. In contrast to previously reported results, the present calculations show that the radon compound, HRnF, is more stable than compounds of the lighter congeners. Trends in the first ionization energies, bond lengths, energies of formation and decomposition, and harmonic vibrational frequencies were discussed and found to be consistent with the periodic trends of the atomic properties of the rare gas atoms.
    The Journal of Physical Chemistry A 08/2010; 114(33):8786-92. · 2.77 Impact Factor
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    ABSTRACT: We performed geometry optimization calculations and ab initio molecular dynamics calculations for hydration models of trivalent ions, Y3+, La3+, Gd3+, and Lu3+, by using molecular orbital calculations to examine the so-called gadolinium break. The geometry optimization calculations revealed that the M–O distances of Y(H2O)83+, Lu(H2O)83+, and La(H2O)93+ calculated at the MP2 level were 2.39 Å, 2.36 Å, and 2.63 Å, respectively, which agreed well with observed values. The calculated Gd–O distance (2.44 Å) of Gd(H2O)83+ also agrees reasonably well with the existing observed values. The differences in the M–O distances arise from the differences in the ionic radii. When the coordination number increased, the degree of decrease in the M–O binding energies per bond (B.E.) occurred in the following order: La3+ < Gd3+ < Y3+ < Lu3+. This order is consistent with the order of the ionic radii’s inverse. In ab initio molecular dynamics calculations, by using the Y(H2O)243+ model we could realize the hydration structure where eight water molecules are located around the Y3+ ion. By using the bigger model of La(H2O)643+, the experimentally suggested structure coordinated by nine water molecules was reproduced.
    Journal of Molecular Structure THEOCHEM 06/2010; 949:28-35. · 1.37 Impact Factor
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    ABSTRACT: Recently, the method of fragment molecular orbital-based molecular dynamics (FMO-MD) was enhanced by including the three-body corrections (FMO3) [Y. Komeiji, Y. Mochizuki, T. Nakano, Chem. Phys. Lett. 484 (2010) 380]. This simulation protocol was applied to a droplet model consisting of a divalent zinc ion and 64 water molecules, in order to investigate the hydration structure in ab initio fashion. The first peak position of the Zn–O radial distribution function (RDF) was evaluated to be 2.05Å at the FMO3-HF/6-31G level of theory, which was in agreement with an X-ray value of 2.06±0.02Å. The coordination number was evaluated to be 6, corresponding to an octahedral coordination.
    Chemical Physics Letters 01/2010; 490(1):41-45. · 2.15 Impact Factor
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    ABSTRACT: We have carried out systematic CASSCF and CASPT2 calculations for the ground states of lanthanide trihalides, LnX3 (Ln=Ce–Yb, X=F, Cl, Br, and I), using model core potentials to investigate the effects of static and dynamic electron correlations on the structures of these molecules. Dynamic electron correlation is found to be indispensable for obtaining reliable bond distances in these molecules. Static electron correlation has little effect on bond distances, although the ground states of LnX3 (Ln=Pr, Nd, Pm, Sm, Dy, Ho, Er, and Tm) have more than two major electronic configurations.
    Chemical Physics Letters 06/2009; 474:28-32. · 2.15 Impact Factor
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    ABSTRACT: Ab initio calculations at the level of CASPT2 with Dunning's correlation consistent cc-pVXZ (X=D, T, Q) basis sets have been carried out for pyrimidine, quinoxaline, phthalazine, and their substituted compounds to find candidates that show a change in the direction of the electric dipole moment for the S(0)-->S(1) transition. The present calculations reveal that 6,7-difluorophthalazine and 6,7-dichlorophthalazine are strong candidates having a large and clear change in the direction of the electric dipole moment on the S(0)-->S(1) transition.
    The Journal of Chemical Physics 06/2009; 130(18):184311. · 3.12 Impact Factor
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    ABSTRACT: We have produced new relativistic model core potentials (spdsMCPs) for the third-row transition–metal atoms from Lu to Hg explicitly treating explicitly 5s and 5p electrons in addition to 5d and 6s electrons in the same manner for the first- and second-row transition–metal atoms given in the previous Letters [Y. Osanai, M.S. Mon, T. Noro, H. Mori, H. Nakashima, M. Klobukowski, E. Miyoshi, Chem. Phys. Lett. 452 (2008) 210; Y. Osanai, E. Soejima, T. Noro, H. Mori, M.S. Mon, M. Klobukowski, E. Miyoshi, Chem. Phys. Lett. 463 (2008) 230]. Using suitable correlating functions with the split-valence MCP functions, we demonstrate that the present MCP basis sets show reasonable performance in describing the electronic structures of atoms and molecules, bringing about accurate excitation energies for atoms and proper spectroscopic constants for Au2, Hg2, and AuH.
    Chemical Physics Letters 01/2009; 476(4):317-322. · 2.15 Impact Factor
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    ABSTRACT: We have developed new relativistic model core potentials (MCPs) for the first-row transition-metal atoms from Sc to Zn, in which 3s and 3p electrons are treated explicitly together with the 3d and 4s electrons. By adding suitable correlating functions, we demonstrated that the present MCP basis sets show reasonable performance in describing the electronic structures of atoms and molecules, bringing about accurate excitation energies for atoms and good molecular spectroscopic constants.
    Chemical Physics Letters 02/2008; 452(s 1–3):210–214. · 2.15 Impact Factor
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    ABSTRACT: A new series of tripods were designed to form anion-responsive, luminescent lanthanide complexes. These tripods contain pyridine, thiazole, pyrazine, or quinoline chromophores combined with amide carbonyl oxygen and tertiary nitrogen atoms. Crystallographic and EXAFS studies of the 10-coordinated tripod-La(NO(3))(3) complexes revealed that each La(3+) cation was cooperatively coordinated by one tetradentate tripod and three bidentate NO(3)(-) anions in the crystal and in CH(3)CN. Quantum chemical calculations indicated that the aromatic nitrogen plays a significant role in lanthanide complexation. The experimentally determined stability constants of complexes of the tripod with La(NO(3))(3), Eu(NO(3))(3), and Tb(NO(3))(3) were in good agreement with the theoretically calculated interaction energies. Complexation of each tripod with lanthanide triflate gave a mixture of several lanthanide complex species. Interestingly, the addition of a coordinative NO(3)(-) or Cl(-) anion to the mixture significantly influenced the lanthanide complexation profiles. The particular combination of tripod and a luminescent Eu(3+) center gave anion-selective luminescence enhancements. Pyridine-containing tripods exhibited the highest NO(3)(-) anion-selective luminescence and thus permit naked-eye detection of the NO(3)(-) anion.
    Chemistry 02/2008; 14(17):5258-66. · 5.83 Impact Factor
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    ABSTRACT: We have produced new relativistic model core potentials (spdsMCPs) for the second-row transition-metal atoms from Y to Cd treating explicitly 4s and 4p electrons in addition to 4d and 5s electrons in the same manner as for the first-row transition-metal atoms given in [Y. Osanai, M.S. Mon, T. Noro, H. Mori, H. Nakashima, M. Klobukowski, E. Miyoshi, Chem. Phys. Lett. 452 (2008) 210]. Using suitable correlating functions together with the split valence MCP functions, we demonstrate that the present MCP basis sets show reasonable performance in predicting the electronic structures of atoms and molecules, bringing about accurate excitation energies for atoms and reasonable spectroscopic constants for AgH.
    Chemical Physics Letters 01/2008; 463:230-234. · 2.15 Impact Factor
  • Masaki Mine, Tetsuo Tsutsui, Eisaku Miyoshi
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    ABSTRACT: The conductance of pi-conjugated systems in the pi-stack direction was examined by comparing zero-bias conductances, transmission spectra and molecular orbitals of two probe systems computed with the combination of quantum calculations and the nonequilibrium Green's function technique. The conductance of (benzene)n (n = 2--5) decreased exponentially as the cluster size increased. The conductance of the benzene dimer in the pi-stack direction increased exponentially as the benzene rings approached, which was speculated with computed transmission spectra and molecular orbitals. The applied bias dependency of the conductance of the benzene dimer was also discussed. It was found that too much applied bias on the two probe systems caused a decrease of the transmission coefficient because of the localization of molecular orbitals.
    Japanese Journal of Applied Physics 01/2008; 47:8033-8038. · 1.07 Impact Factor
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    ABSTRACT: DFT calculations for M@C12H12N6 and M@C12H24O6 (where M=Rb+, Cs+, Sr2+, and Ba2+, C12H12N6=hexaaza[18]annulene, and C12H24O6=18-crown-6) were performed using the recently developed model core potential parametrization. Results show that the ions bind more strongly to C12H12N6 than to 18-crown-6 moiety; the difference is more pronounced for cations with smaller radii.
    Inorganica Chimica Acta. 01/2008; 361(7):2166-2171.
  • Ma San Mon, Hirotoshi Mori, Eisaku Miyoshi
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    ABSTRACT: We investigated the electronic structure of low-lying electronic states of Mn2 using a newly developed relativistic model core potential (spdsMCP). Calculations were performed at complete active space self-consistent field (CASSCF) and second-order multiconfiguration quasidegenerate perturbation theory (MCQDPT2) levels. The MCQDPT2 calculations reveal that the 1Σg+ state is the ground state. Calculated spectroscopic constants are very similar to the results of recent all-electron calculations and experimental values, indicating that the spdsMCP works well for Mn2, which requires a highly correlated calculation. The wave functions of low-lying states are also analyzed at the CASSCF level.
    Chemical Physics Letters 01/2008; 462:23-26. · 2.15 Impact Factor
  • Hirotoshi Mori, Eisaku Miyoshi
    Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/2008; 81(2):235-240.
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    ABSTRACT: We developed new model core potentials (MCPs) for s-block elements from Na to Ra, in which the outer core (n-1)s and (n-1)p electrons are treated explicitly together with the ns electrons. By adding suitable correlating functions, we demonstrated that the present MCP basis sets show excellent performance in describing the electronic structures of atoms and molecules, bringing about accurate ionization potentials of atoms and very good spectroscopic constants of ionic and covalent molecules. The results obtained with the new MCPs are very close to the ones obtained using the all-electron correlation consistent basis sets of Dunning.
    Journal of Computational Chemistry 12/2007; 28(15):2424-30. · 3.84 Impact Factor

Publication Stats

301 Citations
180.76 Total Impact Points

Institutions

  • 1991–2012
    • Kyushu University
      • • Graduate School of Engineering
      • • Faculty of Engineering
      Hukuoka, Fukuoka, Japan
  • 1987–2011
    • Fukuoka Dental College
      Hukuoka, Fukuoka, Japan
  • 2010
    • University of Alberta
      • Department of Chemistry
      Edmonton, Alberta, Canada
  • 2006
    • Nagoya City University
      • Graduate School of Natural Sciences
      Nagoya, Aichi, Japan
    • Tomakomai Komazawa University
      Томакомай, Hokkaidō, Japan
  • 2005
    • Hokkaido University
      • Graduate School of Science
      Sapporo-shi, Hokkaido, Japan
  • 2004
    • Aomori University
      Aomori, Aomori Prefecture, Japan
  • 1997
    • Institute for Molecular Science
      Okazaki, Aichi, Japan