Papers - YAMAMOTO Masahiro
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Surface channeling of fast ions Reviewed
Michi-Hiko Mannami, Kenji Kimura, Kazumasa Narumi, Masahiro Yamamoto, Shizuo Naito
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms 125 ( 1/4 ) 97 - 101 1997
Single Work
Publisher：Elsevier
Fast ions incident at glancing angles on single crystal surfaces are reflected from the surface, and the ion-surface interactions take place while the ions are outside of the solid. Our studies of ion-surface interactions performed at this scattering geometry are reviewed with a particular emphasis on the resonant coherent excitation (Okorokov excitation) of surface-channeled MeV B ions and the energy losses of low-velocity ions which are related to the electron density distribution outside the surface.
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Structure of the metal-liquid interface: self-consistent combination of the first-principles metal calculation and an integral equation method Reviewed
M Yamamoto, M Kinoshita
CHEMICAL PHYSICS LETTERS 274 ( 5/6 ) 513 - 517 1997
Single Work
Authorship：Lead author, Corresponding author Publisher：ELSEVIER SCIENCE BV
This letter contributes to development of microscopic theories for the metal/liquid interface. We report results of the first attempt to combine the first-principles calculation for the metal surface and the reference hypernetted-chain method for the liquid in a fully self-consistent manner. The dipolar liquid/Pt(111) interface is considered. The electron density, liquid structure, and electrostatic potential across the interface are briefly discussed. (C) 1997 Published by Elsevier Science B.V.
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Dependence of the third-order coefficients in Landau free energies for bcc->fcc structural transition on hydrogen concentration in zirconium hydrides Reviewed
Y Ashida, M Yamamoto, S Naito, M Mabuchi, T Hashino
JOURNAL OF APPLIED PHYSICS 82 ( 3 ) 1072 - 1079 1997
Single Work
Publisher：AMER INST PHYSICS
Young's modulus E and the modulus of rigidity G of zirconium hydrides ZrHx(0.9 less than or equal to x less than or equal to 1.65) at 941 and 1001 K have been obtained as a function of hydrogen concentration c by measuring resonance frequencies for bending and torsion vibrations of a polycrystalline wire. As c increases, observed E and G increase in the bcc beta phase, slightly increase linearly in the beta + delta phase, and then decrease in the fcc delta phase. On the basis of a phenomenological free energy in terms of strain components taking account of space group symmetry, two types of Landau expansion of the free energies for the beta phase in terms of the strain components which play an important role in the structural phase transition between the beta and the delta phases are examined. The observed E and G are assumed to be the same as the second-order coefficients of the free energy for the Bain distortions, which occur at the structural phase transition. The dependence of the third-order coefficients on c permits the expanded frets energies to describe the fact that the beta phase is more stable than the delta phase at low c. (C) 1997 American Institute of Physics.
DOI： 10.1063/1.365873
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Yuh Ashida, Masahiro Yamamoto, Shizuo Naito, Mahito Mabuchi, Tomoyasu Hashino
Journal of Applied Physics 80 ( 6 ) 3254 - 3258 1996.9
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Yuh Ashida, Masahiro Yamamoto, Shizuo Naito, Mahito Mabuchi, Tomoyasu Hashino
Journal of Applied Physics 80 ( 6 ) 3259 - 3266 1996.9
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First-principles calculation of the longitudinal phonon in the surface-normal direction of a zirconium(0001) slab: Localization mode at the subsurface Reviewed
M Yamamoto, CT Chan, KM Ho, M Kurahashi, S Naito
PHYSICAL REVIEW B 53 ( 20 ) 13772 - 13776 1996
Single Work
Publisher：AMERICAN PHYSICAL SOC
The energies and amplitudes of the longitudinal vibrational mode in the surface-normal [0001] direction of the fully relaxed zirconium slab with a (0001) surface are calculated with force constants determined from first-principles total-energy and force calculations. A subsurface vibrational mode with frequency above the bulk continuum is found. We attribute the origin of this mode to the hardness of the force constant between the surface and the second layer.
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Masahiro Yamamoto, C. T. Chan, K. M. Ho, Shizuo Naito
Physical Review B 54 ( 19 ) 14111 - 14120 1996
Single Work
Authorship：Lead author Publisher：American Physical Society (APS)
DOI： 10.1103/PhysRevB.54.14111
Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.54.14111/fulltext
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Naito S, Yamamoto M, Miyoshi T, Mabuchi M, Doi M, Kimura M
Journal of the Chemical Society - Faraday Transactions 92 ( 18 ) 3407 - 3410 1996
Joint Work
Publisher：Royal Society of Chemistry (RSC)
DOI： 10.1039/ft9969203407
Other Link： http://orcid.org/0000-0001-8645-2224
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Diffusion of hydrogen in titanium, Ti<inf>88</inf>Al<inf>12</inf>and Ti<inf>3</inf>Al Reviewed
Miyoshi T, Naito S, Yamamoto M, Doi M, Kimura M
Journal of the Chemical Society - Faraday Transactions 92 ( 3 ) 483 - 486 1996
Joint Work
Publisher：Royal Society of Chemistry (RSC)
DOI： 10.1039/ft9969200483
Other Link： http://orcid.org/0000-0001-8645-2224
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Dissolution of hydrogen and deuterium in titanium, Ti94Al6 and Ti3Al Reviewed
Shizuo Naito, Masahiro Yamamoto, Minoru Doi, Masao Kimura
Journal of the Chemical Society, Faraday Transactions 91 ( 13 ) 1967 - 1973 1995
Single Work
The solubility of hydrogen and deuterium in α-, α,β- and β-titanium, Ti94Al6 and in α2-Ti3Al has been volumetrically measured in the ranges of temperature 623-1323 K and hydrogen concentration (atomic ratio) 0.001-0.25. The equilibrium hydrogen pressure at a given temperature and hydrogen concentration has been found to increase greatly as the aluminium content increases. This is explicable on the assumption that aluminium atoms block some of the sites available to hydrogen atoms. In contrast, the heat of solution of hydrogen only slightly increases with the aluminium content and in α-titanium, α-Ti94Al6 and α2-Ti3Al, the ratio of the deuterium pressure to the hydrogen pressure at identical hydrogen and deuterium concentrations is almost independent of the aluminium content. A possible cause of the small dependence of the measured heat and ratio on the aluminium content is discussed and occupation of the tetrahedral site by hydrogen atoms is suggested for α-titanium, α-T94Al6 and α2-Ti3Al. The origin of the sloping plateaus observed in the pressure-composition isotherms for α, β-Ti94Al6 is also briefly discussed.
DOI： 10.1039/ft9959101967
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First-principles calculation of oxygen adsorption on Zr(0001) surface : Possible site occupation between the second and the third layer Reviewed
YAMAMOTO Masahiro
Bull. Amer. Phys. Soc. 40 ( 1 ) 164 1995
Single Work
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ELECTRON-ENERGY-LOSS SPECTRA AND SECONDARY-ELECTRON EMISSION-SPECTRA OF ZR, ZRN AND ZRO2 Reviewed
M KURAHASHI, M YAMAMOTO, M MABUCHI, S NAITO
JOURNAL OF PHYSICS-CONDENSED MATTER 7 ( 24 ) 37 - 4772 1995
Single Work
Publisher：IOP PUBLISHING LTD
Electron energy-loss spectra and secondary-electron emission spectra have been measured for Zr, ZrN and ZrO2. The position and shape of the measured peaks associated with 4p-electron excitation are consistent with the multiplets calculated for zirconium ions possible in Zr, ZrN and ZrO2.
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Electron energy loss spectra of Sc, Ti, V and their oxides Reviewed
M. Kurahashi, M. Yamamoto, S. Naito
Journal of Physics: Condensed Matter 7 ( 35 ) L463 - L468 1995
Single Work
Electron energy loss spectra have been investigated for Sc, Ti, V and their oxidized surfaces. The position and shape of the measured peaks associated with the 3p electron excitation are found to be consistent with 3p63da4sm-3p53dn+14s m transitions calculated for isolated Sc, Ti and V ions.
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ELECTRON ENERGY-LESS FINE-STRUCTURE OF A POLYCRYSTALLINE TITANIUM SURFACE Reviewed
M KURAHASHI, M YAMAMOTO, M MABUCHI, S NAITO
JOURNAL OF PHYSICS-CONDENSED MATTER 7 ( 1 ) 37 - 46 1995
Single Work
Publisher：IOP PUBLISHING LTD
The temperature dependence of the electron energy-loss fine structure (EELFS) of a polycrystalline titanium surface has been measured in reflection mode for electron beams at different incidence angles to the normal of the surface. We have found that within experimental error (about 0.06 Angstrom) the interatomic distance between titanium atoms remains unchanged as the depth from the surface changes and that the EELFS Debye-Waller factor has larger values for larger incidence angles. This result is compared with the reported results of LEED measurements.
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Naito S, Yamamoto M, Doi M, Kimura M
Journal of the Chemical Society, Faraday Transactions 91 ( 22 ) 4143 - 4147 1995
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FIRST-PRINCIPLES CALCULATIONS OF THE SURFACE RELAXATION AND ELECTRONIC-STRUCTURE OF ZR(0001)
M YAMAMOTO, CT CHAN, KM HO
PHYSICAL REVIEW B 50 ( 11 ) 7932 - 7939 1994.9
Joint Work
Publisher：AMERICAN PHYSICAL SOC
The multilayer relaxations of the Zr(0001) surface and the surface electronic structure are studied using first-principles total-energy and force calculations. The distance between the outermost two layers is 4.4-4.7% smaller than the ideal interlayer spacing, while inner layers show oscillatory relaxations. We examined two possible termination sequences for the surface and found that the hcp surface termination is more stable by about 0.06 eV per surface atom as compared to the fee terminated structure. We observed an increase in the local density of states (LDOS) for the surface atoms around the Fermi level relative to the bulk atoms. The increase in the LDOS is found to be closely related to the existence of surface states and resonances around the Fermi level.
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A Theoretical Model for the several Common Stacked Crystals in Arrangement of the stacking sequence of Parallel Atomic Layers in a Simple Crystal Solid Reviewed
Masao Kimura, Masahiro Yamamoto, Mahito Mabuchi, Tomoyasu Hashino
J. Phys. Soc. Japan 63 ( 10 ) 3661 - 3670 1994
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Structural Transition between HCP and FCC Structures with Considering Configurations of the Position Vectors Defined by Several Common Stacked Model Hamiltonian Reviewed
Masao Kimura, Masahiro Yamamoto, Mahito Mabuchi, Tomoyasu Hashino
J. Phys. Soc. Japan 63 ( 10 ) 3714 - 3728 1994
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SOLUBILITY OF HYDROGEN AND DEUTERIUM IN TI3AL Reviewed
M KIMURA, T TSUCHIYAMA, S NAITO, M YAMAMOTO
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS 90 ( 9 ) 1355 - 1356 1994
Single Work
Publisher：ROYAL SOC CHEMISTRY
The solubility of hydrogen and deuterium in Ti3Al has been measured and found to obey Sieverts law. The difference in the solubility between hydrogen and deuterium can be explained by a model in which hydrogen and deuterium atoms perform harmonic oscillations in the tetrahedral site of the Ti3Al crystal lattice.
DOI： 10.1039/ft9949001355
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HIGH-TEMPERATURE DIFFUSION OF HYDROGEN AND DEUTERIUM IN PALLADIUM Reviewed
T MAEDA, S NAITO, M YAMAMOTO, M MABUCHI, T HASHINO
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS 90 ( 6 ) 899 - 903 1994
Single Work
Publisher：ROYAL SOC CHEMISTRY
The diffusivity of hydrogen and deuterium in palladium has been measured at temperatures between 773 and 1373 K and at hydrogen and deuterium concentrations less than 10(-4) H/Pd and D/Pd (atomic ratio). The measured diffusion coefficients for hydrogen (D(H)) and deuterium (D(D)) showed Arrhenius behaviour. The dependence of the ratio D(D)/D(H) on temperature has been explained by a model of diffusion in which a hydrogen atom in an octahedral site of the palladium lattice can jump into the adjacent octahedral site only when local deformation of the palladium lattice assists the jump.
DOI： 10.1039/ft9949000899