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Yoshimi Tsuchiya
1977 Volume 43 Issue 6 Pages
1823-1831
Published: December 15, 1977
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The behaviors of the hydrodynamic fluctuations near the convection threshold are investigated on the basis of the nonlinear hydrodynamic equations with random forces. A nonlinear Langevin equation for the fundamental mode, which becomes unstable near the critical point, is obtained by taking into account the selection rule for the mode-mode coupling caused by the nonlinear interaction of hydrodynamic variables. It is found from the nonlinear Langevin equation that, when the Rayleigh number
R exceeds its critical value
Rc, the convection associated with the fundamental mode sets in and its velocity varies as (
R−
Rc)
1⁄2 and furthermore the second and the third modes depend on the Rayleigh number as (
R−
Rc) and (
R−
Rc)
3⁄2, respectively. By solving the Fokker-Planck equation derived from the nonlinear Langevin equation, we obtain that the fluctuations of the fundamental mode become large as |
R−
Rc|
−1 near the threshold but remain finite at the critical point. It is shown that these results can be applied only to the fluid with the Plandtl number above unity and the behavior of the hydrodynamic variables near the convection threshold depends on whether the Prandtl number is below or above unity.
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Motoyuki Tanaka, Kazuhiro Takahashi
1977 Volume 43 Issue 6 Pages
1832-1838
Published: December 15, 1977
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Using a conventional kinetic theory dynamical behaviours of the spin-one Ising system containing the biquadratic interaction are investigated for various values of the ratio of the bilinear to biquadratic interaction. Expectation values of the dipolar and quadrupolar moment are solved from equations derived in the molecular-field approximation, and their changes near equilibrium in each phase are shown to be described by two characteristic time constants which vary with temperature in different ways. Nonequilibrium relaxations of the system are also investigated numerically in several cases. A remarkable feature is found in flatness property of the expectation values when they approach to the paramagnetic values at temperatures just above the transition temperature of the first-order quadrupolar or ferromagnetic phase transition.
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Kazuo Nakanishi, Hiroyuki Shiba
1977 Volume 43 Issue 6 Pages
1839-1847
Published: December 15, 1977
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The incommensurate (I) states of the triple charge density waves (CDW) in 1T-TaS
2 are studied in details by taking into account a sufficiently large number of harmonics. A domain-like structure of the I-CDW state is shown to be realized as the fundamental wave vector of the I state approaches to the commensurate (“3×1” superstructure) wave vector; the domain boundary is characterized generally by a change of the phase and amplitude of the CDW, and inside the domain an approximately commensurate CDW is stabilized. The nature of the commensurability energy and the coexistence of three CDW’s are reflected in the pattern of the domain-like structure. The successive first-order transitions in 1T-TaS
2 are discussed in this connection. The presence of a domain-like structure, which our theory predicts for the nearly commensurate phase of 1T-TaS
2, is consistent with the recent X-ray photoemission experiment by Hughes and Pollak.
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Takao Goto
1977 Volume 43 Issue 6 Pages
1848-1853
Published: December 15, 1977
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The variations in the magnetic properties of binary Cr–Pt alloys with composition and atomic long-range order were determined from magnetic and X-ray diffraction measurements in the concentration range of 18–50 at. % Cr. The ordered phase of this system has the Cu
3Au-type structure at 22–40 at. % Cr and the CuAu I-type structure at 50 at. % Cr. The effective number of Bohr magnetons and the saturation magnetic moment per Cr atom decrease with increasing Cr content in the highly ordered state of the Cu
3Au-type structure and decrease with atomic disordering. The variation in the effective number of Bohr magnetons with composition and atomic ordering can be explained by assuming that the atomic magnetic moment of Cr decreases in proportion to the average number of Cr atoms occupying its nearest-neighboring sites.
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R. Vijayaraghavan, Kenji Shimizu, Junkichi Itoh, A. K. Grover, L. C. G ...
1977 Volume 43 Issue 6 Pages
1854-1856
Published: December 15, 1977
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The magnitude and the sign of the hyperfine fields determined by NMR at all the nuclear sites in SmAl
2, SmFe
2, SmCo
2 and SmCo
5, at rare earth nuclei in TbAl
2 and TbAg and at Pt nuclei in SmPt
2 are reported.
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Hiroshi Akoh, Masahiro Matsumura, Kunisuke Asayama, Akira Tasaki
1977 Volume 43 Issue 6 Pages
1857-1860
Published: December 15, 1977
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Magnetic susceptibility measurements on
Cr1−xVxCo alloys containing 1 at % Co have been made in the range of
x from zero to 1 over the temperature range 4.2 to 660 K. The susceptibility due to Co impurities above the Néel temperature follows Curie-Weiss law. The magnitude of the effective moment, about 3 μ
B in
CrCo alloy, decreases monotonically with the increase of
x, and the localized moment disappears in
x=0.3 alloy. From the results of magnetic susceptibility and NMR measurements, it is concluded that the coexistence of magnetic and nonmagnetic Co atoms, at least for
x=0.2 and 0.25 alloys, exists and that the formation of localized moment seems to depend on the configuration not only of nearest neighbors but also of long range.
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Masahiro Matsumura, Kunisuke Asayama
1977 Volume 43 Issue 6 Pages
1861-1869
Published: December 15, 1977
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Magnetic state of Co impurity in
Cr1−xVxCo and
Mo1−xRexCo alloys were investigated systematically by NMR.
In
CrVCo alloys, the internal field at
59Co in magnetically ordered state decreases with the increase of
x associated with the decrease of Co moment.
59Co resonances due to nonmagnetic Co atoms were observed for
x≥0.2. The Knight shift,
K, and nuclear spin-lattice relaxation time,
T1, show that Co atoms become gradually magnetic when
x decreases below
x=0.4. For
x=0.2 and 0.25 alloys, the results of NMR and magnetic susceptibility indicate the coexistence of magnetic and nonmagnetic Co atoms.
In
MoReCo alloys,
K and
T1 show that Co atoms become gradually nonmagnetic with the increase of
x.
K and
T1 in both alloy systems were analyzed using the modified Korringa relation which was substantiated by Shiba for the ground state of the Anderson model.
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Takehiro Nakashima, Shigeru Mizuno, Tadashi Ido, Kiyoo Sato, Shigeshi ...
1977 Volume 43 Issue 6 Pages
1870-1878
Published: December 15, 1977
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Atomic diffuse scattering from a single crystal of Au
4Mn with the disordered fcc structure was observed by neutron diffraction in the three dimensional reciprocal space. A cigar type diffuse pattern along the line of [1,
K, 0] with three broad maxima at
K=0.27, 0.50 and 0.73 was obtained. After some corrections and an arrangement of the pattern at the equivalent positions in the reciprocal space, the parameters of atomic short range order and pair interaction up to the 50th neighbor were determined by a method presented by Adachi-Nakashima: J. Phys. Soc. Japan
40 (1976) 25. The reproducibilities from the order parameters and the pair interactions thus determined were examined. The former gives a good reproducibility but the latter not. Origins of the pair interaction of this alloy were discussed.
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Ichiro Ohkoshi, Koichi Shindo
1977 Volume 43 Issue 6 Pages
1879-1883
Published: December 15, 1977
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The pseudopotential of Si crystal is determined self-consistently from the Topp-Hopfield type model potential of Si atom by using the Slater approximation. The crystal energy and compressibility are calculated on the basis of the resultant band structure and the charge density. A good agreement between the calculated values and the experimental ones is obtained with no adjustment such as the zero pressure condition nor fitting to the band structure near the fundamental band gap as done in the usual empirical pseudopotential methods.
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Takehiko Hidaka
1977 Volume 43 Issue 6 Pages
1884-1891
Published: December 15, 1977
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In this paper we describe the theory of nonlinear polarizability of wurtzite-type crystals using
sp3 hybridized wave function model. Negative sign of χ
333(2) of BeO, ZnO and SiC follows naturally from the model with Slater-type wave function and Pauling’s ionicity without any further empirical assumptions. It is pointed out that the overlap of the wave functions of anion and cation leads to a contribution to χ
ijk(2) as large as other terms. The abnormal ratio χ
333(2)⁄χ
311(2) in distorted wurztite-type crystals (BeO, ZnO, SiC and CdS) is also discussed. Its main cause is the bond-ionicity anisotropy Δ
fi=
fix−
fiz in crystals. Δ
fi is proportional to the spontaneous lattice distortion Δ(
c⁄
a), where
c and
a are the lattice constants. Δ
fi⁄Δ(
c⁄
a) is found to be about 3.
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Koji Kajita, Taizo Masumi, Thomas B. Reed
1977 Volume 43 Issue 6 Pages
1892-1905
Published: December 15, 1977
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Anomalous transport phenomena of photoelectrons in pure EuO crystals have been studied over the temperature range from
T=4.2 K to 80 K and in the magnetic fields up to
H=50 kOe by using a fast-pulse technique with blocking electrodes. The Redfield geometry was used to determine directly the value of Hall mobility of photocarriers, μ
H. Anomalous behaviours of photoconductivity such as an abrupt increase below the Curie temperature
Tc=69.5 K and a large negative-magnetoresistance effect around
Tc were observed. The value of μ
H has been measured as a function of both the temperature and the magnetic field. It was directly found that the value of μ
H varies with
H around
Tc; the μ
H-value at
T=63.5 K increases from 90 cm
2/V. sec at
H=0 to 160 cm
2/V. sec at
H=15 kOe. Thus, the anomalous transport phenomema in pure EuO crystals around
Tc have been experimentally confirmed, for the first time, to be mainly due to the mobility change. Experimental results are discussed in terms of the transport theory based on the wide band scheme and the spin disorder scattering due to the
s–
f exchange interaction.
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Mahito Mabuchi
1977 Volume 43 Issue 6 Pages
1906-1911
Published: December 15, 1977
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Dynamical and statistical behaviors of Frenkel excitons in a matter system consisting of
N two-level-atoms and interacting with an external field are studied with the molecular field and random phase approximations. Existence of a phase transition is suggested both in the exciton system and exciton-photon coupled system. This phase transition is the second order transition whose order parameter is the polarizability. A new type of condensation of the photon-exciton coupled wave, in which a macroscopic number of excitons and photons participate, has been found as a result of appreciable contribution of photons to the phase transition. When the incident light is coherent, the condition of phase transition is modified by photon induced exciton-exciton interaction. The energy dispersion of elementary excitations is derived.
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Satoshi Hashimoto, Shigeharu Nagai, Takatoshi Murata
1977 Volume 43 Issue 6 Pages
1912-1919
Published: December 15, 1977
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Optical absorption spectra of Li
1−xNa
xBr and Li
1−xMxI (
M=Na, K, and Rb) measured at liquid nitrogen temperature are reported. In the systems of iodides, the persistent behavior of the first exciton bands is clearly observed. This nature is discussed in connection with the theory of mixed crystals. In Li
1−xNa
xBr the spectral shape changes abruptly at 0.46≤
x≤0.50. In all the systems, additional sharp band is observed on the low energy side of the first exciton band of lithium halides when the concentration of doped alkali ion is less than 10%.
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Hisao Ito, Ryumyo Onaka
1977 Volume 43 Issue 6 Pages
1920-1928
Published: December 15, 1977
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Magnetic circular dichroism (abbreviated as MCD) spectra of the α and β bands in KI are studied. The band shape of MCD of the α band resembles the derivative curve of the absorption band, while that of the β band resembles the absorption band itself. These facts imply that the β center is diamagnetic and the β center is paramagnetic, and that each of the observed bands corresponds to the lowest excited state split by the spin-orbit interaction. From the magnitudes of the MCD and absorption bands the orbital
g-value of the valence hole in the perturbed excitons is found to be 0.7∼0.8. The reduction of the orbital
g-value from unity is interpreted as the effect of the intermixing of the three hole functions around the lattice defects.
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Shoji Masunaga, Ryoichi Takaue
1977 Volume 43 Issue 6 Pages
1929-1932
Published: December 15, 1977
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Emission and excitation spectra of KCl:Tl, KBr:Tl, KI:Tl, NaCl:Tl and NaBr:Tl have been measured up to 36 kbar at room temperature. In the case of potassium halide, when the host crystal is transformed from the NaCl-type to the CsCl-type structure by applied pressure, the emission spectra show a discontinuous blue shift and grow significantly on their high energy sides, resulting in the overlap of the excitation and emission spectra. In the case of NaCl:Tl, the excitation and emission spectra also partially overlap each other with increasing pressure. It is discussed that the parameter S of Haung and Rhys in the Tl
+-center decrease with increasing pressure.
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Jun Hatano, Fujio Suda, Hideo Futama
1977 Volume 43 Issue 6 Pages
1933-1940
Published: December 15, 1977
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Detailed observations of domain structure in triglycine selenate crystals have been made in special respect to the orientations of the 180° domain-walls by an improved powder-deposition technique. Two kinds of flat wall can be seen; one is parallel to the crystallographic (001) planes and another is to the (\bar201) planes. The angular dependence of the wall-energy density has been numerically calculated on the basis of the Zhirnov-type continuum theory. Two minima in the energy are obtained, each of which corresponds to the wall orientations observed experimentally. The numerical values of elastic stiffness, electrostrictive, dielectric constants and correlation-energy coefficients required for the calculation have been also determined experimentally. The theoretical and experimental results of wall orientations are discussed in comparison with those of triglycine sulfate crystals.
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Kazuo Gesi
1977 Volume 43 Issue 6 Pages
1941-1948
Published: December 15, 1977
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Dielectric properties of single crystal (NH
4)
3H(SO
4)
2 were measured in a pressure and temperature region of
p\lesssim8.5 kbar and −100°C\lesssim
T\lesssimRT. A broad peak of the dielectric constant along the
c*-direction which is found around −25°C at 1 atm becomes sharp and intense as pressure increases, and then above 5.0 kbar a ferroelectric phase (Phase VI) appears. Further increase in pressure stabilizes another ferroelectric phase (Phase VII) in a lower temperature region. The VI–VII transition is of the first order. Temperature dependence of the spontaneous polarization was measured at various pressures. A two-sublattice model is presented to interpret the pressure and temperature dependence of the dielectric properties of (NH
4)
3H(SO
4)
2.
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Kazuo Gesi
1977 Volume 43 Issue 6 Pages
1949-1953
Published: December 15, 1977
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Dielectric properties of single crystal (NH
4)
3H(SeO
4)
2 were measured below room temperature. Two phase transitions were found at around +2°C and at −92°C. A λ-type peak of the dielectric constant along the
c-direction is found at −92°C, and the crystal shows ferroelectricity below the transition. The temperature dependence of the spontaneous polarization was measured by a pyroelectric method. The Curie temperature linearly increases with increasing hydrostatic pressure up to 8.5 kbar with a slope of 2.3 deg kbar
−1.
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Kenji Ema, Katsumi Hamano, Kazuo Kurihara, Ichiro Hatta
1977 Volume 43 Issue 6 Pages
1954-1961
Published: December 15, 1977
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The specific heat of triglycine selenate was investigated with an a.c. calorimetry technique in the temperature range −170°C to +90°C including the Curie point at 22°C. A λ-type anomaly with a sharp peak at
Tc was seen in the range about −60°C to
Tc. The plateau region reported by Strukov
et al. was not observed. The specific heat curve below
Tc was fitted very well with a mean-field theory of an Ising-dipole system which took into account the effect of lattice distortion. A parameter Δ which describes the strain dependence of the interaction energy was determined to be 0.303<Δ<0.324, indicating that the transition is of the second order and very close to the Curie critical one which occurs when Δ=1⁄3. A slight excess specific heat with logarithmic temperature dependence was observed in the paraelectric phase within
T−
Tc\lesssim10 K. This anomaly is considered to be due to the critical fluctuation.
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Seishi Yamamoto, Yasuko Suematsu, Yasuhiro Shinnaka
1977 Volume 43 Issue 6 Pages
1962-1967
Published: December 15, 1977
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The phase transition in RbNO
3 from the NaCl type cubic phase I to the rhombohedral phase II is investigated with X-ray diffraction method. In the phase I, from the observations of X-ray temperature diffuse scattering, it is found that
c44⁄
c11 has abnormally small value 0.03 and a diffuse intensity concerning only
c44 increases at the rate of 8 % per 10°C as temperature decreases to the I→II transition temperature. A lattice relationship is found at the transition: In the phase II, the lattice is distorted by only an increase in angle between axes with decreasing temperature. A model of orientational disorder among eight orientations of NO
3− is proposed in both phases. These results suggest that the coupling between the orientation of NO
3− and the shear strain plays an important role in this transition.
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Yasuhiro Shinnaka, Seishi Yamamoto, Yasuko Suematsu
1977 Volume 43 Issue 6 Pages
1968-1973
Published: December 15, 1977
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The cubic-rhombohedral transition in NaCl type RbNO
3 crystal is theoretically treated as that induced by a coupling between orientation and shear strain. On the basis of a proposed 8-orientation model of NO
3− ion, the expression of linear coupling is obtained. The theoretical results are compared with experimental results reported in the preceding paper (J. Phys. Soc. Japan
43 (1977) 1962). The observed transition temperature of the first order transition and the observed temperature dependence of X-ray diffuse scattering in the cubic phase are well explained quantitatively by a value of
C2⁄
c44, where
C is a coupling constant. The estimation of the coupling constant from the interatomic forces also gives a support on the validity of the present treatment.
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Toru Matsuo, Hideji Suzuki
1977 Volume 43 Issue 6 Pages
1974-1981
Published: December 15, 1977
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The phonon scattering by vibrating dislocation dipoles and the scattering by twin boundaries are discussed to explain the thermal conductivity of deformed crystals of bismuth and its dilute alloys. The scattering of phonons by vibrating dislocation dipoles was calculated by employing Ninomiya’s formulae of eigenvibrations of an edge dislocation dipole, and the results were successful to explain the thermal conductivity of bismuth crystals deformed by slip. The thermal conductivity of twinned bismuth crystals was calculated by assuming that the scattering of phonons obeys the scattering law of a long wavelength acoustic wave scattered by a plane interface between twin-related media. The results are in reasonably good agreement with the experiments.
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Katsumi Tanimura, Touichi Okada
1977 Volume 43 Issue 6 Pages
1982-1990
Published: December 15, 1977
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Thermoluminescence mechanism has been studied from the view-point of clarifying kind of reactions of radiation-induced defects responsible for the emission in KBr crystals irradiated at 77 K. The dependence of glow curves on the kind of alkali impurity and on Na
+ concentration, and the response of glow peaks to the F-light illumination were studied. Correlations between glow peaks and reactions of color centers were made clear as follows. The recombination between neutral Frenkel pairs, Br
i0+F, is assigned as the main origin of thermoluminescences in non-activated specimens. Annihilation of the V
K center due to the thermal migration of the hole and to the reaction of freed Br
i− are also found to be responsible for the emission.
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Takashi Hashimoto
1977 Volume 43 Issue 6 Pages
1991-1997
Published: December 15, 1977
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The residual stress is examined by analyzing the magnetic anisotropy, and its association with the columnar grain structure is discussed. It is shown that there exists a close correlation between the changes in the residual stress and the electrical resistivity during annealing, and that the magnitude of the residual stress is roughly proportional to the volume fraction of the grain boundary region. These results suggest that the residual stress is related to the structural defects in the grain boundary region. The recovery process of the magnetic anisotropy is composed of two stages with activation energies of 1.2 and 2.0 eV, which are associated with the stress relief and the grain growth, respectively. The stress relief occurs by grain boundary diffusion.
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Eiichi Yagi, Ryukiti R. Hasiguti
1977 Volume 43 Issue 6 Pages
1998-2005
Published: December 15, 1977
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Electron microscopy on slightly vacuum-reduced rutile single crystals with a composition of about TiO
1.996 revealed the presence of isolated planar faults with {312} fault plane. The displacement vector
R of this fault was determined to be
R\simeq1⁄2〈10\bar1〉. Discussion was made on the relation between such planar faults and defect centers observed in EPR experiments performed on the same specimens. The result on the displacement vector supports the interpretation of
W-spectrum observed in the EPR experiments.
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Shinji Hayashi, Nobuyuki Nakamori, Junzo Hirono, Hitoshi Kanamori
1977 Volume 43 Issue 6 Pages
2006-2012
Published: December 15, 1977
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The infrared transmission spectra of MgO small cubes were measured over a wide range of the dielectric constant of surrounding medium. The results were analysed on the basis of the theory of surface normal modes in cubic particles. Observed shift of the main-absorption peak (located between the bulk-phonon frequencies ω
T and ω
L) with respect to the dielectric constant of surrounding medium is in close agreement with the theoretical prediction. The position and shape of experimental curves of absorption coefficients can be reproduced fairly well by the theory of cubes. In addition, one type of the samples showed the absorption peak at ω
T, which is interpreted as due to the formation of particle chains, while the other type did not show the absorption peak due to the separation of particles from each other.
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Shoji Masunaga, Nobuyuki Goto, Akira Matsushima, Atsuo Fukuda
1977 Volume 43 Issue 6 Pages
2013-2020
Published: December 15, 1977
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Pressure effects on the emission spectra excited by the A absorption have been observed at various temperatures between 168 and 293 K in KI, KBr, and KCl doped with Tl
+, In
+, or Ga
+. When both of the A
T and A
X bands appear, the A
T band grows at the expense of the A
X band as the pressure increases. Particularly, in KBr: Tl
+ and KBr: In
+, the A
X band disappears almost completely under 7.5 k bar. When only the A
T band appears as in KCl: Tl
+ and KCl: In
+, no drastic change has been observed up to 7.5 k bar. The pressure effects have been discussed on the basis of the quadratic Jahn-Teller effect by correlating the relaxed excited states for the A
T and A
X bands to the tetragonal and trigonal minima on the
Γ4− (A) and
Γ1− adiabatic potential energy surfaces respectively.
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Haruo Takahashi, Ryumyo Onaka
1977 Volume 43 Issue 6 Pages
2021-2029
Published: December 15, 1977
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By using synchrotron radiation as the light source, the near-normal incidence reflection spectra of KMgF
3 and NaMgF
3 were measured in the XUV region, from which the spectra of imaginary part of the dielectric constant were obtained by means of the Kramers-Kronig transformation. The largest sharp peak observed at 11.9 eV in KMgF
3 was assigned to
Γ15(upper)→
Γ1 exciton (
A exciton) and the small hump at 13.5 eV to the
Γ15(lower)→
Γ1 exciton (
B exciton). The line shapes of the
A and
B excitons were calculated theoretically by taking into account the interference effects between the A and B channels. It was found that the interchannel mixing due to the electron-hole Coulomb and exchange interactions has an important effect on the experimentally observed line shapes.
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Hira Lal Kharoo, O. P. Gupta, M. P. Hemkar
1977 Volume 43 Issue 6 Pages
2030-2035
Published: December 15, 1977
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The modified form of the non central force model which considers the electron-ion interaction term of Kreb’s model to the Clark-Gazis-Wallis type angular forces is considered to calculate the Debye-Waller exponents at different temperatures for three bcc metals Sodium, α-iron and cromium and compared with the available X-ray measurements in terms of the temperature parameter Y of the Debye Waller factor, characteristic Debye temperature θ
M and the mean square displacement u
−2 of the atoms. The theoretical results are found to be in a reasonably satisfactory agreement with the experimental values.
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S. P. Khare, R. Shingal, B. B. Srivastava
1977 Volume 43 Issue 6 Pages
2036-2041
Published: December 15, 1977
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The elastic scattering of intermediate energy electrons from hydrogen molecules has been investigated using the optical eikonal approximation. The optical potential consists of the first order static potential and a second order potential which accounts for the polarization effects as well as for the absorption effects. The exchange effects have been included through the Ochkur approximation. The differential cross sections have been calculated over the complete angular range for incident energies of 30, 50, 100 and 200 eV and compared with available experimental data and other theoretical results. The present results demonstrate for the first time the effects of absorption on the electron-molecule elastic scattering.
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Seiichi Gotô, Tadao Uyama, Norio Satomi, Hiroshi Itô
1977 Volume 43 Issue 6 Pages
2042-2048
Published: December 15, 1977
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The ion heating process of a kilovolt plasma obtained by a rapid magnetic compression is studied experimentally. The initial plasma for compression is produced by the encounter of two deuterium plasma streams. For the spectroscopic evaluation of the ion temperature, a small quantity of helium is added to the deuterium gas. According to time-resolved measurements of Doppler profiles of a HeII line, the ion heating process is divided into two stages: phase I up to 240 ns from the ignition of the compression and phase II hereafter. In phase I, most of measured Doppler profiles take the Gaussian forms and the heating rate is 1∼2 eV/ns. In phase II, each profile from 250 ns to 500 ns shows a two-temperature distribution. The ion temperature is 1.7 keV at 700 ns and the heating rate is 4 eV/ns around this time. Finally, the ion temperature reaches 3∼4 keV.
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Hiroshi Itô, Seiichi Gotô, Tadao Uyama, Norio Satomi
1977 Volume 43 Issue 6 Pages
2049-2055
Published: December 15, 1977
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The process of a two-staged ion heating of counter streaming plasma flows under a rapidly increasing magnetic field is studied by measuring plasma parameters and changes of fields. In the early stage of the compression, ions of the initial plasma are heated up to 300∼400 eV till 240 ns by the reflected ions from the magnetic piston existing near the wall. By a stable and strong azimuthal current sheet around the plasma column existed already in the encounter process, a large magnetic well is formed after 240 ns. By the interaction with this moving magnetic barrier, ions are accelerated effectively and the ion temperature reaches 3∼4 keV at last. The density and the temperature of electrons are (2∼3)×10
15cm
−3 and 300 eV, respectively.
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Hisanori Iwakura, Mitsuo Kono
1977 Volume 43 Issue 6 Pages
2056-2061
Published: December 15, 1977
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The possibility of the parametric decay instability is examined in the system of ion acoustic waves which have a non-decay type of dispersion relation in a linear sense. The finiteness of the pump wave amplitude yields the frequency shift due to the nonlinear self-interaction, making the resonant decay condition satisfied. The threshold of this instability is discussed.
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Masayoshi Sugihara, Masatada Ogasawara
1977 Volume 43 Issue 6 Pages
2062-2067
Published: December 15, 1977
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An expression for the turbulent collision frequency is derived by summing up the most dominant terms from each order in a perturbation expansion in order to obtain the nonlinear saturation level of the dissipative trapped ion instability. Numerical calculation shows that the anomalous diffusion coefficient at the saturated state is in good agreement with the result of Kadomtsev-Pogutse when the effect of ion Landau damping is taken into account.
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Yukio Midzuno, Ryo Sugihara
1977 Volume 43 Issue 6 Pages
2068-2073
Published: December 15, 1977
Released on J-STAGE: June 01, 2007
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The problem of the energy absorption of a monochromatic Langmuir wave of finite (but small) amplitude in a rarefied plasma, a problem which was first treated by Zakharov and Karpman (1962), is reexamined. Emphasis is laid on the requirement that the matching of the distribution function of the untrapped particles with the Maxwellian at a large velocity must be made more accurately than done previously. The calculation shows that the energy absorption rate of the wave of the amplitude φ
0 is proportional to φ
03⁄2, in contrast to the previous result which is proportional to φ
01⁄2.
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Ryogo Hirota
1977 Volume 43 Issue 6 Pages
2074-2078
Published: December 15, 1977
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A nonlinear partial difference equation which reduces to the Toda equation in the continuous-time limit, is obtained and solved using the dependent variable transformation. The
N-soliton solution for this equation has the same functional form as that found in the Toda equation.
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Ryogo Hirota
1977 Volume 43 Issue 6 Pages
2079-2086
Published: December 15, 1977
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A nonlinear partial difference equation which reduces to the sine-Gordon equation in the continuum limit, is obtained and solved by the method of dependent variable transformation.
N-soliton solutions, the Bäcklund transformation and the inverse scattering form for this equation are presented.
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Takeo Osawa, Jun-ichiro Tada
1977 Volume 43 Issue 6 Pages
2087-2089
Published: December 15, 1977
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A periodic wave solution traveling with a low velocity is given using the perturbation method. This periodic solution becomes a slow traveling pulse given by Casten, Cohen and Lagerstrom (Quart. Appl. Math.
32(1975) 365) when a period becomes infinity.
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Koichi Imanaka, Takeshi Iida, Hiroshi Ohkura
1977 Volume 43 Issue 6 Pages
2090A
Published: December 15, 1977
Released on J-STAGE: May 29, 2007
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Hiroshi Yoshie
1977 Volume 43 Issue 6 Pages
2090B
Published: December 15, 1977
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Hajime Takayama
1977 Volume 43 Issue 6 Pages
2091-2092
Published: December 15, 1977
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We introduce a new decoupling method for the configuration averages which appear in the effective field theory for disordered magnets, in order to take into account possible spatial correlation of spins in each configuration of the random variables. Using the method we obtain an interpolation scheme between the Edwards-Anderson model and the Mattis model, which are the two extremes with respect to the degree of such correlation.
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Isao Yamada, Tatsuo Nishizaki
1977 Volume 43 Issue 6 Pages
2093-2094
Published: December 15, 1977
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In the one-dimensional system TMMC, the position of the half-field EPR line changes remarkably with angle between the static field and the c-axis, whereas in the two-dimensional system K
2MnF
4, there is almost no change in its position. The large shift in TMMC is thought to come solely from the dynamic effect due to the long-time tail of the spin correlation functions.
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Kazumi Horai, Masanori Arakawa, Hideo Takeuchi
1977 Volume 43 Issue 6 Pages
2095-2096
Published: December 15, 1977
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The ligand fluorine ENDOR spectrum in perovskite-fluoride KCdF
3 doped with Mn
2+ have been measured at 4.2 K using 34 GHz EPR spectrometer. The angular dependence of the spectrum evidently shows that the fluorine octahedra are distorted from the regular positions with tilting angles of about 6, 10 and 10 degrees around the [001], [100] and [010] axes in the pseudo cubic phase of the crystal and these components reflect the domain structure.
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Masahito Yahagi
1977 Volume 43 Issue 6 Pages
2097-2098
Published: December 15, 1977
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The measurement of the thermal expansion coefficient for LiAl
1−xIn
x system is performed and it is found that the variation of these measured values with
x has a maximum at half the composition (
x=0.5). This phenomenon seems to rise in the deformation due to the arrangement of aluminum and indium atoms with different atomic radii. Grüneisen constants of LiIn crystal are estimated to be 2.66 and 3.22 from the thermal expansion coefficient and specific heat.
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Shozo Sawada, Yoshihiro Shiroishi, Akitoshi Yamamoto, Masaaki Takashig ...
1977 Volume 43 Issue 6 Pages
2099-2100
Published: December 15, 1977
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It has been found that Rb
2ZnCl
4 shows phase transitions at about −81 and 29°C, respectively and is ferroelectric in the
a direction below −81°C.
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Shozo Sawada, Yoshihiro Shiroishi, Akitoshi Yamamoto, Masaaki Takashig ...
1977 Volume 43 Issue 6 Pages
2101-2102
Published: December 15, 1977
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Rb
2ZnBr
4 has been found to show phase transitions at about −86 and 18°C, respectively and to be ferroelectric in the
a direction below −86°C.
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Shigeru Nakayama, Toru Ogawa
1977 Volume 43 Issue 6 Pages
2103-2104
Published: December 15, 1977
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By means of the recursive perturbation method developed by Hioe and Eberly, we present an analytic expression of general fourth-order effects in the frequency shifts of new coherence resonances and multiphoton transitions for the general case that a spin-1/2 atom interacts with an oscillating rf field in optical pumping. Moreover, the validity of the theoretical results is checked by an optical-rf double resonance experiments with cesium vapor, and agreement between observed and calculated results becomes close.
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Makoto Shiho
1977 Volume 43 Issue 6 Pages
2105-2106
Published: December 15, 1977
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The absorption spectra of solid benzene grown under different conditions have been measured from 1100 Å to 2500Å. We have found that the spectrum of solid benzene grown at high temperature (170 K) is quite different from that of solid benzene grown at low temperature (60 K∼120 K). Brief discussions on the origin of the differences in the spectra are given.
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Naohisa Wada, Takasi Sagawa
1977 Volume 43 Issue 6 Pages
2107-2108
Published: December 15, 1977
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The valence bands of all-trans retinal
1 and β-carotene were measured by X-ray photoelectron spectroscopic method (XPS). It is shown that the experimental results correspond qualitatively to the calculated energy levels of molecular orbital (MO).
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Kuniya Fukuda, Hidetoshi Suemitsu
1977 Volume 43 Issue 6 Pages
2109-2110
Published: December 15, 1977
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Emission from C-, N- and O-impurity ions in linear z-pinch He plasma was measured in λ 1500–500 Å region. The experimental results suggest that the emission of the transitions 2s2p
m–2s
22p
m−1 in impurity ions X
z+1 is induced by the charge exchange process, He
+(1s)+X
z(2s
22p
m)→He(1s
2)+X
z+1* (2s2p
m), and that this process leads to the population inversion in X
z+1 ions.
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