Tsuyoshi Yamaguchi

A new magnetic symmetry of the rare-earth orthochromites and orthoferrites ($\mathrm{RM}{\mathrm{O}}_{3}$) below the second N\'eel temperature due to the reordering of the rare-earth spins is proposed. It is shown that the magnetic symmetry group is lowered to the subgroup of index two, thereby keeping the unit cell invariant. The proposed symmetry is shown to be consistent with the previously observed spin configuration of $\mathrm{RM}{\mathrm{O}}_{3}$ such as GdCr${\mathrm{O}}_{3}$, DyFe${\mat

We have measured the absorption and the resonance Raman spectra of a solvatochromic dye, phenol blue, in liquid and supercritical solvents. We have found anomalous solvent dependence of the absorption bandwidth in liquid solvents: the width has apparently no correlation with the absorption peak shift. On the other hand, we have found good linear correlation between the absorption peak shift and the peak position of the resonance Raman bands (the CN and the CO stretching modes). The relative inte

The frequency-dependent shear viscosities of four representative imidazolium-based room-temperature ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([bmim][TFSA]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF(6)]), and 1-methyl-3-octylimidazolium hexafluorophosphate ([omim][PF(6)]), are measured from 5 to 205 MHz with shear impedance spectroscopy. A relaxation is observed in the measured

A theoretical treatment for vibronic levels of an interacting electron and vibration system is developed so as to calculate g -values in paramagnetic resonance and vibronic structures in optical spectra simultaneously, under the assumption that the electrons interact with localized vibrations. The variations of the g -values and absorption and emission spectra with the interaction strength are shown for weak and intermediate interactions, choosing Cu 2+ ions in II-VI semiconductors as an object

We have performed molecular dynamics (MD) simulations of the nonpolar solvation dynamics in simple fluids composed of particles interacting through the Lennard-Jones (LJ) 12–6 potential or its repulsive part. The attractive or the repulsive part of the solute–solvent interaction is assumed to change on the excitation of a solute. We have followed the transition energy fluctuation of the solute by the equilibrium simulation. The division of the LJ potential followed the method of WCA [J. W. Weeks

The frequency-dependent viscosity and conductivity of various ionic liquids were measured experimentally, and their mean relaxation times were determined. The relaxation times of the viscosity and conductivity were approximately correlated with their respective zero-frequency limiting values. The Walden products, however, appeared to have no correlation with the ratio of the relaxation time of viscosity to that of conductivity in general. When the alkyl chain of the cation is as short as butyl,

The shear relaxation spectra of three imidazolium-based ionic liquids, 1-methyl-3-octylimidazolium chloride ([C(8)mim][Cl]), 1-methyl-3-octylimidazolium hexafluorophosphate ([C(8)mim][PF(6)]), and 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C(12)mim][TFSA]) were measured and compared with the intermediate scattering functions determined with neutron spin echo (NSE) spectroscopy. The shear relaxation is slower than that predicted from the relaxation of the main peak of the

The electric and mechanical relaxation spectra of the solutions of lithium perchlorate (LiClO(4)) in propylene carbonate (PC)-based mixed solvents are studied. The frequency-dependent dielectric susceptivity and electric conductivity from 0.05 to 20 GHz are determined with microwave reflectometry, and the shear relaxation from 15 to 95 MHz is measured with quartz-crystal shear impedance spectroscopy. An electric relaxation is observed at several hundreds of megahertz in a PC solution of LiClO(4)

The mode-coupling theory for molecular liquids based on the interaction-site model is applied to a representative molecular ionic liquid, dimethylimidazolium chloride, and dynamic properties such as shear viscosity, self-diffusion coefficients, reorientational relaxation time, electric conductivity, and dielectric relaxation spectrum are analyzed. Molecular dynamics (MD) simulation is also performed on the same system for comparison. The theory captures the characteristics of the dynamics of the

The adatom model of the Si(111) 7\textcopyright{}7 structure obtained by scanning tunneling microscopy, which is an experiment in real space, is extended to take into account the displacement of atoms. The 12 first-layer adatoms in the unit cell have an ${\mathrm{sp}}^{3}$-electron configuration; the 12 second-layer dangling-bond-site atoms have ${\mathrm{sp}}^{2}$; the second-layer dangling-bond-site atom at the center of the half unit cell has ${\mathrm{sp}}^{2.5}$. The adatoms shift upward by

All of the energy matrices of the p-d Coulomb and the exchange interactions and the spin-orbit interaction of p electrons of the electron system p5dN (N=1-9) are calculated based on the strong-field scheme of the ligand field theory. By diagonalising, at the same time, the matrices of not only the interactions mentioned above but also the d-d interactions and the cubic field, the following three kinds of spectra of a series of transition-metal compounds are calculated: (i) the X-ray 3p-shell pho

Abstract Superpositioning of negative dc bias in dual-frequency capacitively coupled plasmas (dc-superposed (DS)-CCP) was realized for the selective etching of carbon-doped silicon oxide (SiOCH) films over carbon-doped amorphous silicon (SiC) films, while the dc bias exceeded about −800 V. When a dc bias of −1200 V was superposed on 60 MHz VHF power on the top electrode opposed to a wafer on the bottom electrode biased with 13.56 MHz power, a selectivity of above 50 for SiOCH over SiC was obtain

We have measured the excitation photon energy dependence of the resonance Raman spectra of a solvatochromic dye, phenol blue (PB) in various solvents from nonpolar to dipolar ones, including supercritical fluids of trifluoromethane and carbon dioxide. We have found that the band peak positions of the C=N stretching mode of PB appear to change with the excitation laser frequency in polar solvents. On the other hand, no dependence of the band peak positions on the excitation frequency is found in