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Tomotake Yanagita
1978 Volume 45 Issue 2 Pages
359-366
Published: August 15, 1978
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The relation between the longitudinal development and the lateral distribution of electrons in extensive air shower is theoretically investigated by a simulation study. The results show that the features of the first collision are not the main factor that govern the fluctuation of the lateral distribution. The attenuation length and the lateral distribution of electrons are strongly correlated. The correlation, which is described by a simple formula, is insensitive to the gross value of inelasticity but is sensitive to the details of energy distribution among the secondary particles. A comparison of experimental results with this relation suggests that the multiple meson production mechanism at air shower energies (\gtrsim100 TeV) is different from that at \lesssim1 TeV.
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Yoshiyuki Toba, Harutaka Sakaguchi, Akira Goto, Fumihiko Ohtani, Noriy ...
1978 Volume 45 Issue 2 Pages
367-373
Published: August 15, 1978
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Angular distributions of elastic and inelastic scatterings on
28,29,30Si were measured with a 51.9 MeV proton beam. The blocking effect in the core-excitation of
29Si due to the antisymmetrization between the excited-core and the extra neutron was investigated. Optical model and distorted wave Born approximation analyses were performed using a macroscopic form factor for a collective excitation of
28,29,30Si and a microscopic form factor for a single particle excitation of
29Si. In the case of
29Si, a mixing of an excited-core state and a single particle state was taken into account following the intermediate-coupling model calculation. Deformation parameters β
2 of
28,29,30Si were extracted to be 0.42, 0.36 and 0.36, respectively. The reduction in the deformation parameter of
29Si is considered to manifest the blocking effect of 25±14% in the core-excitation.
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H. R. Verma, A. K. Sharma, Nirmal Singh, P. N. Trehan
1978 Volume 45 Issue 2 Pages
374-381
Published: August 15, 1978
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The energies and intensities of various gamma ray transitions in Tm
169 nuclide populated in the electron capture decay of Yb
169 have been measured using a 64.1 cc. Ge(Li) detector coupled with 4096 channel analyser. The coincidence measurements have been made using Ge(Li)–NaI(Tl) slow-fast coincidence set up. The singles and coincidence measurements confirm the existance of 285, 295, 304.0, 328.0, 336.5, 354.7, 370.8, 579.5 and 600.3 keV γ-transitions from the decay of Yb
169. The presence of 718.5 keV level in the level scheme of Tm
169 is also confirmed from the electron capture decay of Yb
169. In addition to the energy and intensity measurements, gamma-gamma angular correlation measurements on five cascades, namely 198–118, 198–110, 261–110, 177–130 and 177–(21)–110 keV have been done using Ge(Li)–NaI(Tl) fast coincidence set up. Out of these, the 261–110 keV cascade has been attempted for the first time. On the basis of these measurements, the multipole mixing in 261, 198, 177, 130 and 110 keV γ-transitions have been calculated. A comparison of experimental transition probabilities with those of single particle estimates show a collective behaviour of Tm
169 nucleus.
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Hajime Takayama
1978 Volume 45 Issue 2 Pages
382-389
Published: August 15, 1978
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The spin glass phase (SGP) and the random ordered phase (ROP) of random quenched Ising spin systems with
z>>1,
z being the coordination number, are eximined by the effective field theory. Thereby the effect of the ground-state degeneracies as well as the ‘frustration effect’ are taken into account by a phenomenological parameter. The restricted SGP, which is a SGP but not an ROP, is not found unless obviously incorrect approximation of type 1=〈σ
i2〉
T≅〈σ
i〉
T2 is used, where 〈 〉
T indicates the thermal average in a given configuration of the random interactions. We also examine various properties of the ROP, such as the spectrum of the effective field, divergence of the nonlinear susceptibility at the transition point, and the specific heat.
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Yoshio Kuramoto
1978 Volume 45 Issue 2 Pages
390-396
Published: August 15, 1978
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The ground state of a two-dimensional electron system in a strong magnetic field is investigated under the condition that only the ground Landau level is partially filled. Within the unrestricted Hartree-Fock approximation the ground state proves to be a charge-density-wave (CDW) state. When the density is low, wave functions of nearby lattice sites are well separated so that the CDW is regarded as a classical Wigner crystal. It is shown that the amplitude of the CDW is very large at arbitrary densities. Density dependence of the ground state energy is discussed using (1) a unidirectional CDW structure which allows one to take full account of the exchange effect, and (2) the square lattice for which self-consistent solution is obtained in the case of the half-filled Landau level as well as in the low density classical regime.
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Tôru Moriya, Yoshinori Takahashi
1978 Volume 45 Issue 2 Pages
397-408
Published: August 15, 1978
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Spin fluctuations and the thermodynamical properties of itinerant electron ferromagnets are discussed from a general point of view by using a simple model with a small number of physical parameters and approximations in the functional integral formalism. We give unified expressions for the Curie temperature and the magnetic susceptibility which interpolate between the weakly and strongly ferromagnetic limits. In general, both the transversal and longitudinal components of the local spin fluctuations contribute to the Curie constant and the former (latter) is predominant in the local moment (weakly ferromagnetic) limit. It is pointed out that the amplitude of the local spin fluctuations can be saturated when there is an upper or lower bound of the energy band not too far from the Fermi level, resulting in a Curie-Weiss susceptibility of a local moment type, even without well-defined local moments. A transition between two different kinds of local spin states can also be expected in some cases.
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Yoshihiro Ishibashi, Hiroyuki Shiba
1978 Volume 45 Issue 2 Pages
409-413
Published: August 15, 1978
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The successive phase transitions from a prototype to an incommensurate phase and then to a commensurate phase are studied on the basis of a model thermodynamic potential where the instability of a one-dimensional representation is assumed. The model is suitable to a unified description of the phase transitions in SC(NH
2)
2 and NaNO
2 which show ferroelectricity in their commensurate phases. The incommensurate states of the model and its dielectric properties are analysed by taking harmonics into account. It has turned out that the present model can satisfactorily reproduce the transitions actually observed in SC(NH
2)
2 and NaNO
2.
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Shoji Kashida
1978 Volume 45 Issue 2 Pages
414-421
Published: August 15, 1978
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The mechanism of the successive phase transitions in K
2PbCu(NO
2)
6 is studied on the basis of an order-disorder model. By the use of the Fourier transform of the order parameter, the ordering energies are compared in the various phases.
The antiferro-distortive phase III of K
2PbCu(NO
2)
6 has a lower ordering energy, and stable at low temperatures. A phase transition from the phase III to the incommensurate sinusoidal phase II is occurred because of an entropy gain. The free energies and order parameters are calculated as functions of temperature.
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Ken-ichi Kumagai, Toshimasa Matsuhira, Kunisuke Asayama
1978 Volume 45 Issue 2 Pages
422-430
Published: August 15, 1978
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Spin echo NMR and ac susceptibility measurements have been performed at 60 mK∼4.2 K in (Ce
1−xGd
x)Ru
2. The sharp superconducting transition is confirmed for
x≤0.110. The NMR signals associated with the ferromagnetically ordered Gd atoms are observed down to
x=0.105 in zero external field and to
x=0.095 with applying field. The hyperfine field at Gd site changes as −206+88·
x kOe. The intensity of the signal in zero field decreased rapidly in accordance with the appearance of superconductivity. The temperature, concentration and external field dependence of the transverse relaxation time
T2 show that
T1 is governed mainly by the Weger mechanism. The rapid increase of
T1 with lowering temperature for 0.105≤
x≤0.110 indicates a possible appearance of small energy gap associated with superconducting state. The results support the coexistence of superconductivity and ferromagnetism.
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Masafumi Yamamoto
1978 Volume 45 Issue 2 Pages
431-438
Published: August 15, 1978
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We studied the effect of the anisotropic crystal structure of TaSe
3 on its superconducting properties. The upper critical field
Hc2 was estimated from the resistive transition curve as functions of the field direction and temperature. The large anisotropy of
Hc2 was found in the plane containing the
b-axis and the normal of the (\bar201) plane with the maximum along the
b-axis.
Hc2 was also anisotropic in the plane perpendicular to the
b-axis with the maximum along the
c-axis. The simple one-dimensional picture for the structure of TaSe
3 cannot explain the experimental angular dependence of
Hc2.
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Toshio Urano, Yutaka Nakai
1978 Volume 45 Issue 2 Pages
439-443
Published: August 15, 1978
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The magnetism of CoAl compound near stoichiometry has been interpreted in terms of local moment on the excess Co atoms. To investigate this model, we have observed small angle magnetic scattering of neutrons in Co-rich CoAl compounds at liq.He, liq.N
2 and room temperatures. It is shown after the cluster model analysis that this scattering is not due to the Coal cluster but the precipitated Co atom cluster. This is supported by X-ray diffraction experiments.
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Katsuya Kikuchi, Tomonao Miyadai, Hiroki Itoh, Tsunaomi Fukui
1978 Volume 45 Issue 2 Pages
444-449
Published: August 15, 1978
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The polarization analysis for the (200)M1 reflection has been made on a twin free single crystal of NiS
2 at ∼5 K. The final polarization (
Pf) was measured as a function of the rotating angle (\varphi) about the scattering vector. (
Pf is approximately expressed by −0.95 cos 2\varphi.) The antiferromagnetic structure with respect to the first kind ordering was determined under the assumption that a particular domain distribution is not realized in the sample. The previously proposed non-collinear structure was confirmed.
A weakferromagnetic moment more than 0.01 (μ
B) was observed on each nickel ion forming the pyrite structure by measuring the flipping ratio of the (400) nuclear reflection. Mechanisms for weakferromagnetism are discussed.
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Nozomu Inoue, Tadashi Sugawara
1978 Volume 45 Issue 2 Pages
450-457
Published: August 15, 1978
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NMR of
195Pt was studied at helium temperatures in the Pt metal with addition of 3d, 4d and 5d transition metal solutes. The satellite lines separated from the main line were observed in
PtV,
PtCr,
PtNb,
PtRe and
PtRh at the solute concentration less than 0.5 at%. From the analysis of these satellite lines, the spacial distribution function of the change of the magnetic susceptibility at Pt sites was derived. It is shown that the observed change of the bulk magnetic properties due to the solute atom can be reproduced well by this distribution function and that the change is localized in the vicinity of the solute atom. The effect due to the spin polarization of conduction electrons by the localized magnetic moment of solute expected for
PtCr is found to be negligibly small possibly due to its high Kondo temperature.
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Masaaki Matsui, Soshin Chikazumi
1978 Volume 45 Issue 2 Pages
458-465
Published: August 15, 1978
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Thermal expansion coefficients of Fe–Ni alloys were analyzed by using the Grüneisen equation. The anomalous thermal expansion coefficient term, α
a, was calculated by subtracting the lattice vibration term described by Grüneisen theory from the experimental data. The anomalous volume change obtained by integrating α
a was analyzed in terms of the two-states model of iron, the energy separation of which is assumed to be a function of the exchange field and temperature. The temperature dependence of the energy splitting is in good agreement with that of the spontaneous magnetization.
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Kan Usami
1978 Volume 45 Issue 2 Pages
466-475
Published: August 15, 1978
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The magnetoresistance of itinerant electron antiferromagnets is studied on the basis of the two band model where the electrons in one conduction or s-band are the current carriers and are scattered by the spin fluctuations due to the d electrons. The self-consistent renormalization theory of spin fluctuations is applied to the d electrons. The resistivity shows a cusp at the Néel temperature and becomes linear in
T at high temperatures. The resistivity under a perpendicular field shows a negative magnetoresistance for small fields and a narrow peak at the antiferromagnetic to paramagnetic transition point
Hc. In the case of a parallel applied field with the uniaxial anisotropy, we expect a large increase in the magnetoresistance on both sides of the spin flopping transition point. Numerical calculations are made with the use of the free electron gas model with Umklapp processes.
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Takeshi Hiraoka
1978 Volume 45 Issue 2 Pages
476-478
Published: August 15, 1978
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Hall effects in Ce
1−xLa
xAl
2 have been measured in the temperature range from 4.2 K to room temperature. The extraordinary Hall resistivity (EHR) showed a complicated temperature dependence at low temperatures and strong deviations from Curie law at lower temperatures. These behaviors were shown as the result of Ce
3+ influenced by the crystal field. The concentration dependence of EHR showed proportional behavior at lower temperatures indicating skew scattering by Ce
3+ ions.
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Shin’ichi Takeda, Yoshimi Tsuchiya, Shigeru Tamaki
1978 Volume 45 Issue 2 Pages
479-483
Published: August 15, 1978
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The magnetic susceptibilities of molten Pb–Te alloys have been measured as a function of concentration and temperature. Curves of the isothermal susceptibilities show a rather large deviation from the linearly interpolated ones at the composition near Pb
50Te
50. From these results, a convenient criterion on the electron localization in liquid semiconductors is discussed.
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B. P. Singh, L. P. Pathak, M. P. Hemkar
1978 Volume 45 Issue 2 Pages
484-486
Published: August 15, 1978
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The phonon waves in transition metals Palladium and Platinum along three directions of high symmetry have deen studied in the frame work of simplified Fielek model (1975). The computed dispersion curves show a very good agreement with the experimental results.
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Ichiro Hatta, Masato Shibuya
1978 Volume 45 Issue 2 Pages
487-494
Published: August 15, 1978
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By the experiments of the relaxation process of the electrical resistivity in Ni
3Mn alloy its relaxation time was found to become longer as temperature approaches the transition point. It was verified that below the transition temperature thus obtained relaxation time coincides with that previously obtained for the order parameter by Collins and Teh’s neutron diffraction experiments. From the results in the wide temperature range the critical index of the linear relaxation time was analyzed to be 1.0. In CuZn alloy the tendency of critical slowing-down was revealed to take place by measuring the similar electrical resistivity relaxation.
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Kazuhiko Tsuji, Makoto Yao, Hirohisa Endo
1978 Volume 45 Issue 2 Pages
495-500
Published: August 15, 1978
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Electrical conductivity σ of liquid Te and its dilute alloys containing Co, Cr, Au and Ag has been measured up to 1500°C and up to 1100 bar. The measured temperature coefficient of σ at constant pressure, (∂ ln σ⁄∂
T)
p, is positive and large near the melting temperature, decreases with increasing temperature and becomes negative above 850°C. On the other hand, the estimated temperature coefficient of σ at constant volume, (∂ ln σ⁄∂
T)
V, remains positive even at high temperature. These and other features of the temperature and pressure dependences of σ for liquid Te are discussed in connection with the ionic structure. The change in σ with addition of transition and noble metals to liquid Te is also discussed on the basis of the concept of d-resonant scattering and sp-d hybridization.
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Toshi Sanada, Kiyoshi Matsushita, Tyuzi Ohyama, Eizo Otsuka
1978 Volume 45 Issue 2 Pages
501-504
Published: August 15, 1978
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Electron transfer process from neutral donor to neutral acceptor in germanium has been observed at liquid helium temperatures in the form of a slowly decaying photoconductivity tail after the flash of the band-gap light. The decay time constant is governed by the leakage flux of room temperature black body radiations upon the sample. Through analyzing the d.c. conductivity as well as Hall data, microwave cyclotron resonance and far-infrared magneto-absorption, the carrier capture cross sections by neutral impurities are determined as a function of temperature: 8×10
−17 cm
−2 for the capture of electrons at neutral acceptors and 5×10
−16 cm
−2 for that of holes at neutral donors, at 4.2 K with a dependence of
T−2.
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Sadao Adachi, Chihiro Hamaguchi
1978 Volume 45 Issue 2 Pages
505-514
Published: August 15, 1978
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Resonant Brillouin scattering in CdS has been studied at room temperature by making use of piezoelectrically inactive
TA phonon domains obtained by mode conversion upon partial reflection of acoustoelectrically amplified
TA phonon domains at the end surface. It has been found that the dispersion of Brillouin scattering efficiency shows a new scattering maximum at a photon energy very close to the ground-state discrete exciton energy. A damping effect on the scattering mechanism has been discussed to explain the observed dispersion. The theoretical prediction based upon Loudon’s light scattering theory has shown a quite good agreement with the present results when the damping effect is taken into account. The dispersion of photoelastic constant (
P66) has been determined from the present data and compared with the piezobirefringence analyses.
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Koi Sato, Shuichi Iwabuchi, Jun Yamaguchi, Yosuke Nagaoka
1978 Volume 45 Issue 2 Pages
515-521
Published: August 15, 1978
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We investigate the structural phase transition in TTF–TCNQ at 38 K by the use of a model of coupled phasons. Taking account of the coupling between charge density waves with wavevector 4
kF, we find that a commensurate structure with the 4
a periodicity along the
a-axis is stabilized at zero temperature, and that a first-order phase transition takes place from it to an incommensurate screw-type structure when temperature increases.
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Seizo Morita, Takashi Noguchi, Nobuo Mikoshiba
1978 Volume 45 Issue 2 Pages
522-527
Published: August 15, 1978
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We have investigated the transverse photoconductance in
n-InSb in magnetic fields up to 30 kG at 4.2 K. A small number of hot electrons were excited by weak irradiation of white light without raising the average temperature of conduction electrons. We observed magnetophonon oscillations in the photoconductance in the samples with carrier concentrations from
n=1.4×10
14 cm
−3 to
n=2.0×10
15 cm
−3. We found that the resonance minima of the oscillations due to the energy relaxation of the photo-excited electrons appear at higher magnetic fields with the increase of carrier concentrations. These shifts are interpreted as the effect of the Fermi energy due to the degeneracy of conduction electrons and are similar to the Burstein-Moss effect in the shifts of the optical absorption edge in heavily doped
n-InSb.
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Yosuke Kayanuma, Yasuhiro Kondo
1978 Volume 45 Issue 2 Pages
528-536
Published: August 15, 1978
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A systematic approach to the vibronic problem of bound polaron is proposed taking advantage of spherical symmetry of the system. The interaction modes of LO phonon classified according to the angular momentum quantum number are introduced and the Hamiltonian is rewritten in the form which is manifestly invariant under rotation. The theory is applied to the analysis of the transient absorption spectra due to the transition from the relaxed excited state to higher excited states of the
F-center in alkali halides. A good fit between the theoretical prediction and the experiment is obtained and the final states of the transition are assigned to be 3
p state and its phonon side bands perturbed through vibronic interactions.
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Hiroyasu Nakata, Katsumasa Fujii, Eizo Otsuka
1978 Volume 45 Issue 2 Pages
537-544
Published: August 15, 1978
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Far-infrared magnetoplasma absorption due to electron-hole drops in pure germanium is observed in laser transmission measurements for eleven wavelengths (84 to 513 μm). From the oscillatory behavior in short wavelength absorption, it is concluded that the carrier-pair density in the drop remains constant (2.2×10
17 cm
−3) up to 20 kOe and increases to 2.7×10
17 cm
−3 at 50 kOe after first decreasing to 2.0×10
17 cm
−3 at ∼25 kOe. The relaxation time in the drop is calculated from the linewidth of the peak of 337 μm absorption at ∼38 kOe and it has a temperature dependence of the form 1⁄τ=α+β
T2 with α=(2.1±0.1)×10
11 s
−1 and β=(1.2±0.1)×10
10 deg
−2s
−1. It is strongly suggested that carrier-carrier scattering is the dominant mechanism for the relaxation process in the electron-hole drop.
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Masaki Taniguchi, Shin-ichiro Narita, Norio Hasegawa, Michihiro Kobaya ...
1978 Volume 45 Issue 2 Pages
545-552
Published: August 15, 1978
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Impurity concentration effects on
D− states in Sb-doped germanium have been investigated by means of long-wavelength photoconductivity at 0.38 K and 1.46 K. Higher energy shifts of the spectra with increasing the impurity concentration suggest the existence of
D− complexes in the samples with Sb-concentrations from 2×10
14 cm
−3 to 1×10
16 cm
−3, and [111]-stress effects on the complexes are also studied. A drastic change of the spectral shape at the concentration of 2×10
16 cm
−3 in the steps of increasing the concentration is ascribed to the formation of the
D− band.
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S. Plesko, R. Kind, J. Roos
1978 Volume 45 Issue 2 Pages
553-557
Published: August 15, 1978
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Structural phase transitions in CsPbCl
3 and RbCdCl
3 have been investigated by
133Cs and
87Rb nuclear magnetic resonance. The space groups of the room temperature phase in CsPbCl
3 and of two unknown phases in RbCdCl
3 could be clarified. Thus both perovskites show the same phase sequence from cubic
Pm3
m-O
h1 to tetragonal
P4⁄
mbm-D
4h5, orthorhombic
Cmcm-D
2h17 and further orthorhombic
Pnma-D
2h16.
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Masaaki Takashige, Shunsuke Hirotsu, Shozo Sawada, Katsumi Hamano
1978 Volume 45 Issue 2 Pages
558-564
Published: August 15, 1978
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Temperature dependence of the piezoelectric constants, elastic compliance coefficients and thermal expansions of ferroelectric Ca
2Pb(C
2H
5CO
2)
6 have been measured in a wide temperature region including the ferroelectric-paraelectric phase transition point. The piezoelectric constants
d31 and
d33 show marked anomalies at the transition point. The constant
d31 changes its sign at about 10°C, whereas
d33 is negative throughout the ferroelectric phase. The elastic compliance coefficient
s33D shows a small but distinct anomaly at the transition point. From the result of thermal expansion measurement, the temperature dependence of spontaneous strain was obtained. It was found that the relation between polarization and strain can not be described by Devonshire’s phenomenological theory of ferroelectric phase transition. These results are compared with the published data on isomorphous Ca
2Sr(C
2H
5CO
2)
6.
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Hiroyasu Shimizu, Akio Oguri, Naohiko Yasuda, Sanji Fujimoto
1978 Volume 45 Issue 2 Pages
565-570
Published: August 15, 1978
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This paper is concerned with the hydrostatic pressure dependence of dielectric properties and the results of the thermal expansion measurements around the I–II phase transition (186.5°C at 1 atm) of NH
4LiSO
4. The observed pressure coefficient of the transition temperature is d
T1c⁄d
p=9.8 deg/kbar from which the volume electrostrictive coefficient is obtained to be Σ
j=13Q1j*=−4.1×10
−9 cgs esu. The calculated value of spontaneous volume change at
T1c is in good agreement with the experimental value of
Vs=−6×10
−4. The pressure dependence of the Curie constant and the temperature dependence of
Vs are discussed by the help of a phenomenological theory including the latent transition parameters associated with prototype→I→II phase transitions.
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Toshio Osaka
1978 Volume 45 Issue 2 Pages
571-574
Published: August 15, 1978
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Specific heat and lattice constants of ferroelectric NaNH
4SO
4·2H
2O were measured in a wide temperature range covering the transition temperature. The transition entropy was estimated to be
ΔS=0.79 cal·mole
−1·deg
−1. The spontaneous tensile strains were obtained to be
xx=5.0×10
−3,
yy=2.1×10
−3 and
zz=3.2×10
−3 at −185°C. The results were discussed thermodynamically with the help of additional results of dielectric measurements made near the transition temperature.
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Etsuo Matsuo, Mikio Tsuji
1978 Volume 45 Issue 2 Pages
575-580
Published: August 15, 1978
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Expressions for the energy density and the energy flow are derived for the electromagnetic surface wave (surface plasmon) on a semi-infinite metal surface by using the hydrodynamic approximation. A proof is given for the equality between the group velocity and the energy velocity. It is also shown that the direction of the energy flow in the metal is the same as that of propagation of the surface wave for sufficiently large wave numbers. This is contrary to the case in the local approximation.
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Tokiko Ohata, Tetsusuke Hayashi, Shigeharu Koshino
1978 Volume 45 Issue 2 Pages
581-585
Published: August 15, 1978
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New emission bands have been observed at 450 nm and 341 nm when a crystal of KI doped heavily with Tl
+ was excited with ultraviolet light near 285 nm at 5 K. An absorption band has been found at 284.5 nm from the excitation spectrum. Dependence of the emission intensity on the concentration of Tl
+ shows that this luminescence is due to (Tl
+)
2 centers.
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Tadao Mochizuki, Koichi Shimoda
1978 Volume 45 Issue 2 Pages
586-594
Published: August 15, 1978
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A dynamic equation of atoms irradiated by a laser light in a magnetic field is applied to the light modulation experiment of atoms, whose excited states are not optically connected with the ground state. The resonance for the fluorescent light as a function of magnetic field is derived. The resonance curve for the fluorescent light from the lower level is found to be a superposition of resonance curves of two different widths. The broad component is a manifestation of the atomic coherence of the lower level. The narrow component is attributed to the atomic coherence of the upper level which is transferred to the lower level by spontaneous emission. The decay rate of the upper level is included in the expression of the resonance curve for the fluorescent light from the lower level.
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Tadao Mochizuki, Koichi Shimoda
1978 Volume 45 Issue 2 Pages
595-603
Published: August 15, 1978
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In this experiment Xe atoms are pumped to the excited states with an r.f. discharge and irradiated by the 3.99 μm Xe laser on the 5d[1/2]
00→6p[1/2]
1 transition. Fluorescent light from the 6p[1/2]
1 level is observed to be modulated when the atoms are subjected to a low-frequency rotating field in perpendicular to the static field. The natural lifetime of the 6p[1/2]
1 level is obtained to be 56±3 ns.
The 3.50 μm laser on the 5d[7/2]
30→6p[5/2]
2 transition is also used. The light modulation signal of the fluorescence from the 6p[5/2]
2 level as a fuction of the magnetic field is a superposition of resonance curves of two different widths. The narrow component is a manifestation of atomic coherence of the 5d[7/2]
30 level which is transferred to the 6p[5/2]
2 level. The natural lifetime of the 5d[7/2]
30 level is obtained as 73±9 ns from the study of the 6p[5/2]
2 level.
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Yasunori Yamazaki, Ryuichi Shimizu, Kazuyuki Ueda, Hatsujiro Hashimoto
1978 Volume 45 Issue 2 Pages
604-611
Published: August 15, 1978
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The electron impact spectra have been measured for electron energies between 300 eV and 1000 eV and scattering angles between 50° and 110°. The ratio of the inelastic to elastic cross section has been less than about 5×10
−2 for 6
1P and 6p′
3P excitations in the energy regions mentioned above. The angular dependences of both the cross sections for 6
1P and 6p′
3P excitations have been similar but rather smoother than that of the elastic one. Strictly forbidden 7
1S excitation has been observed in the electron impact energies between 300 eV and 500 eV.
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Seiji Mizuhashi
1978 Volume 45 Issue 2 Pages
612-616
Published: August 15, 1978
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The normal modes and frequencies of A
2u species which correspond to the Pseudo-Jahn-Teller active vibration of iron-porphin compound are determined. The lowest frequency takes almost constant value 227.6 cm
−1 on the wide range of the force constant parameter between iron and porphin.
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Nobuo Kobayashi, Yoh Itoh, Yozaburo Kaneko
1978 Volume 45 Issue 2 Pages
617-625
Published: August 15, 1978
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Vibrational excitation of CO, CO
2 and N
2O by Li
+ impact was studied with an ion energy-loss spectrometer. The excitation takes place in strongly forward scattering above 400 eV, and absolute total cross sections of excitation are obtained easily. For CO, the cross sections of 0→1 and 0→2 excitation are obtained. For CO
2, the cross sections for the excitation of (010), (020), (001) and (011) levels are determined. The excitation of the symmetric stretching mode (100) is not observed. For N
2O, the excitation cross sections of (100), (010), (001), (002) and (101) levels are obtained. The experimental results are compared with the first Born approximation, and a possibility of determining the infrared intensities is discussed.
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Chiaki Murase
1978 Volume 45 Issue 2 Pages
626-634
Published: August 15, 1978
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Mode coupling effects in dynamical region (the wave number
k≅10
8 cm
−1 and the time
t≅10
−13∼10
−12 s) of simple liquids have been studied theoretically on the basis of the generalized Langevin equation to consider the long tail of the normalized memory function
n(
k,
t) of transverse-current correlation function. From the truncation approximation of the continued-fraction expansion we obtain
n(
k,
t)≅λ(
k)
n0(
k,
t), where λ and
n0 are both dimensionless, and called enhancement factor and kinetic normalized memory function, respectively. The kinetic normalized memory function
n0(
k,
t) shows the long tail
t−2⁄3 due to the mode-coupling effects in dynamical region. Numerical calculations give the intensity
n0(
k,
t≅10
−12 s) of the order 10
−4 and λ of the order 10
2. These results agree with computer experiments.
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Jiro Todoroki
1978 Volume 45 Issue 2 Pages
635-642
Published: August 15, 1978
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Stability of long wave length toroidal theta pinch with
l=0,
l=±1, and
l=±2 corrugating magnetic field is investigated with the aid of the sharp boundary-constant pressure model. The stability criterion is obtained for the outward derivative of the specific volume (
Remark: Graphics omitted.) with respect to the magnetic field without plasma to be negative on the plasma-vacuum surface. It is also found that the growth rate of the
n=0,
m=1 mode to vertical and horizontal displacement is different.
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Nobuo Yajima, Masayuki Oikawa, Junkichi Satsuma, Chusei Namba
1978 Volume 45 Issue 2 Pages
643-651
Published: August 15, 1978
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The nonlinear Schrödinger equation with a nonlocal-nonlinear term, which describes modulated Langmuir waves with the nonlinear Landau damping effect, is solved by numerical calculations. The effects of nonlinear Landau damping on solitary wave solutions are studied. The results show that the solitary waves deform in an asymmetric way changing its velocity. The time evolutions of a periodic modulation are also studied.
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V. K. Garg
1978 Volume 45 Issue 2 Pages
652-659
Published: August 15, 1978
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A theoretical study of the stability of fully-developed axial flow in a concentric annulus is presented. The coupled, linear, ordinary differential equations governing the propagation of the infinitesimal disturbance through the fluid are solved numerically for the complex eigenvalues, each of which defines a mode of propagation. The integration starts at the outer wall by means of a series solution and is continued to the inner wall by the fourth order Runge-Kutta method. An eigenvalue search technique is used to ascertain the number of eigenvalues within a closed region of the complex eigenvalue plane. It is found that the axial flow in the annulus is spatially stable to infinitesimal axisymmetric disturbances upto a modified Reynolds number of 10,000.
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Yuko Oshima
1978 Volume 45 Issue 2 Pages
660-664
Published: August 15, 1978
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When two similar vortex rings travel along the common axis of symmetry in the same direction, the game of passage of one vortex ring through the other was successfully realized both in air and in water. The phenomenon depends on the Reynolds number,
Re, based on the initial traveling speed of vortex rings and the diameter of the ejecting orifice, and also depends on the time interval between two puffs of fluid by which the two vortex rings are produced. The region in the
Re-
T plane in which the game of passing-through is observed was experimentally determined both for air and for water, where
T denotes a non-dimensional time interval. It was found that the region for water was smaller than that for air.
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Yasuo Hashizume, Norito Ikeda
1978 Volume 45 Issue 2 Pages
665-673
Published: August 15, 1978
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Non-linear interactions among two surface waves and an internal wave which satisfy the resonance conditions such that
k1=
k2+
k3 and ω
1=ω
2+ω
3,
k and ω being wave-number vector and frequency, have been investigated using a two-layer fluid model in which each layer has different density and finite depth.
Interaction equations for slowly varying amplitudes have been derived by the analysis to second order of amplitude, and solved. Total energy and momentum of an interacting triad are shown to be conserved to this order. The time scale which characterizes interactions has been calculated for a wide range of wave-number and various density differences.
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Tsunehiko Kakutani, Nobuyoshi Yamasaki
1978 Volume 45 Issue 2 Pages
674-679
Published: August 15, 1978
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This paper deals with weakly nonlinear long gravity waves on a stably stratified two-layer fluid. By using the reductive perturbation method, it is found that the fast mode is always governed by a Korteweg-de Vries (K-dV) equation whose coefficients depend on the thickness ratio and the density ratio. On the other hand, the slow mode is also governed, in general, by another K-dV equation except near and at the critical thickness ratio. At the critical thickness ratio, however, the slow mode is shown to be governed by a modified K-dV equation with cubic nonlinearity and near the critical thickness ratio it is governed by an equation of a combined form of the K-dV and modified K-dV equation. Steady solitary wave solutions to these equations are investigated in detail. A special solution representing a dispersive bore or hydraulic jump is also found.
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Hiroyuki Nagashima, Yoshimitsu Amagishi
1978 Volume 45 Issue 2 Pages
680-688
Published: August 15, 1978
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A nonlinear transmission line equivalent to the exponential lattice of Toda was obtained with the proper understanding of nonlinear properties of a capacitor used in a shunt branch. The character of a soliton is observed to follow the prediction given by Toda with respect to the shape and velocity of the soliton. The details of interaction of two solitons moving in the opposite or same direction are also found to be in good agreement with the theory. The dissipation effect on the soliton due to the small losses in the passive elements of the network is discussed in the continuum limit.
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Takeshi Inoshita, Kenji Nakao, Hiroshi Kamimura
1978 Volume 45 Issue 2 Pages
689
Published: August 15, 1978
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Masaharu Tokunaga, Toshirou Yagi
1978 Volume 45 Issue 2 Pages
690
Published: August 15, 1978
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Fumiko Yonezawa, Takashi Odagaki
1978 Volume 45 Issue 2 Pages
691-692
Published: August 15, 1978
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We propose one possible way of avoiding the breakdown of analyticity of average Green’s functions based on the cluster coherent potential approximation for substitutionally disordered systems. Our assertion is that nonanalyticity would not occur when a one-particle total hamiltonian is partitioned into the sum of homomorphic single-cluster hamiltonians and the CPA condition is applied to one of these homomorphic subhamiltonians. Using an example of homomorphic partition into double-site clusters, we show that the results for disordered one- and three-dimensional systems with site-diagonal randomness lend support to our assertion.
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Takashi Odagaki, Fumiko Yonezawa
1978 Volume 45 Issue 2 Pages
693-694
Published: August 15, 1978
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We apply the homomorphic cluster coherent potential approximation (HCPA) to systems with off-diagonal disorder, and show that average Green’s functions based on this approximation are analytic. On the other hand, the ordinary cluster CCPA for off-diagonal randomness yields nonanalytic solutions. In order to understand the problem of analyticity, we examine the fundamental features of nonanalytic solutions. The breakdown of analyticity is related to the existence of off-real axis branch points on the complex energy plane, the latter in turn being equivalent to the appearance of singularities in some implicit functions containing the average Green’s functions.
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