The first three moments of the γ-ray multiplicity distribution have been calculated for the massive-transfer residue. Importance of the sign of the third moment, i.e., skewness, is pointed out by showing that the skewness is likely to be positive in the case of massive transfer, being contrary to the case of complete fusion.

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Resonant Brillouin scattering spectra are measured on a layer semiconductor 2H-PbI₂. The observed exciton polariton dispersion in the direction parallel to the c-axis is interpreted by a two branch polariton model yielding the translational exciton mass of 2.3 m₀ and the effective dielectric constant of 10. The anisotropy of the effective mass is estimated to be m_⁄⁄⁄m_⊥=3.4 for exciton and 4.4 for conduction electron, respectively.

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The transverse and Hall resistivities of electrons in Si-MOS inversion layer have been measured at T\simeq0.5 K in the magnetic fields H=9.0 T and 10.5 T, at the gate voltages around the transverse resistivity minima. The Hall resistivity is found to be integral fractions of h⁄e² in precision better than 2 parts in 10⁷ over the concentration of electrons ieH⁄hc ranging from 1×10¹² cm⁻² (i=4) to 3×10¹² cm⁻² (i=12).

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The ESR spectrum of SeO₄³⁻ radicals doped in the DKDP single crystal has been found to behave near T_c in a manner quite different from those of SeO₄³⁻ in KDP and Cr⁵⁺ in DKDP. The spectrum consists of two kinds of signals from paraelectric and ferroelectric phases of the crystal in a narrow temperature range around T_c. The range is estimated to be about 4 K. Above this range, only high symmetric paraelectric spectrum can be observed and the low symmetric ferroelectric one does not survive in contrast with the results on the KDP: SeO₄³⁻ and DKDP: Cr⁵⁺ previously reported.

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The optical and X-ray examinations of CsHSeO₂ were made at temperatures above and below the 128°C transition (T_c). It is found that CsHSeO₄ is ferroelastic with a large spontaneous shear strain, x_z⁰=7.9×10⁻², at room temperature and becomes paraelastic above T_c.

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The two independent CDW transitions and the behavior of the hall constant of NbSe₃ are explained by the independent nestings of the Fermi surfaces obtained by the LCAO–Xα–SCF relativistic band calculation.

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Total absorption method has been applied to 4s^{2 1}S₀-4snp ¹P₁ (6≤n≤10) and to 4s^{2 1}S₀-3d4p ¹P₁ in calcium in the presence of krypton. The determined rate coefficient for Kr-induced broadening increases from 11 to 59×10⁻⁹ cm³s⁻¹ as n increases from 6 to 9. This result is reproduced well by a calculation based on a classical broadening theory in which the collision interaction is assumed to be a superposition of the polarization potential and the Fermi potential.

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Spectra of highly ionized molibdenum were observed with a low inductance vacuum spark by means of a 10.7 m grazing incidence spectrograph. Wavelengths of the spectra of 3d⁹–3d⁸4p transition of Mo XVI were determined and new line identification in the wavelength region from 47 Å to 48 Å were carried out by comparing with spectra theoretically predicted from the relativistically corrected Hartree-Fock calculation.

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This letter describes the open ended device with a non-planar magnetic axis of which the torsional angle can be changed easily. It is shown experimentally that the value of the diamagnetic signal obtained at a non-planar configuration is more than that at a planar one under the same condition.

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We investigate the explode-decay mode solutions of the two-dimensional KdV equation. It is shown that by exploiting the linearity of the associated inverse scattering formalism, a hierarchy of infinitely many solutions can be generated from the previously known similarity type solutions.

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The periodic perturbation is imposed on the Belousov-Zhabotinsky reaction by means of periodically repeated stirring of the reacting mixture. Since the flow of the mixture caused by the stirring includes oxygen gas from the surface, the reaction is modulated by a periodic stirring and an entrained or a nonperiodic oscillation is observed depending on the repetition rate of the stirring. The sample data amplitudes of nonperiodic oscillations are analysed by using the Lorenz plot, and well-defined single-valued transfer functions are obtained which give positive Liapounov numbers and have period three points. We conclude thus that the system exhibits chaotic behavior.

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The energies and relative intensities of 85 gamma rays following the decay of ^106gRh have been measured with a high precision in the present studies. It has been possible to resolve most of the discrepancies existing in the previous measurements regarding the presence and placement of several weak gamma transitions and energy levels in ¹⁰⁶Pd. A new gamma ray has been observed at 2185.7 keV and has been placed between 3320.3 and 1133.76 keV energy levels of ¹⁰⁶Pd. Also a new level has been proposed at 2717.4 keV so as to fit 1159.9 keV gamma ray between 2717.4 and 1557.5 keV levels of ¹⁰⁶Pd.
Gamma-gamma angular correlation measurements have been done in case of 17 cascades. From the directional correlation analysis, spin assignments of 2⁺ to the levels at 2308.79, 2902.5 and 2917.9 keV, 0⁺ to the levels at 2828.2, 2877.9, 3082.8 and 3221.3 keV, and 1⁺ to the level at 3055.3 keV have been confirmed. A unique spin assignment of 2⁺ has been made to 2705.1 keV level. Also, the multipole mixing ratios in the 1050, 1796, 1927, 1988, 2193, 2391, 2406 and 2542 keV transitions have been evaluated.

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The gamma rays accompanying the decay of 8s ¹⁹⁸Ir were studied with a Ge spectrometer. Transitions with energies (intensities) of 407.4±0.3 (100±7) and 507.0±0.3 (76±10) keV have been confirmed. Additional transitions in ¹⁹⁸Pt have been sought up to energies of 2700 keV; none has been observed. An upper limit of 15% is placed on the intensity of any new transition in ¹⁹⁸Pt with an energy above 700 keV.

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The form factor of a separable interaction between a pair of particles is an important input in a three-body calculation for a transfer reaction. To construct the same, a method based on the work of Bolsterli and Mackanzie is tried for a simple case viz. α-d pair, the inputs in this calculation being the phase shift of α-d elastic scattering and the α-d separation energy of ⁶Li. Finally the wave function of the relative motion of α-d clusters in the ground state of ⁶Li, as derived from the calculated form factor, is compared with the available information on it from the experimental data on the ⁶Li(π⁻, nn)⁴He reaction.

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Beta-ray spectrum in ¹⁰³Ru decay has been measured placing main emphasis on determination of the highest β-ray component. From comparison with the Q_β systematics, we concluded that the highest β-ray component feeds to the ground state of ¹⁰³Rh directly, and not to the 39.7-keV isomeric state of ¹⁰³Rh as has been widely accepted. The decay scheme was modified and the spin and parity of the ground state of ¹⁰³Ru was confirmed to be 3/2⁺ as proposed in recent studies on ¹⁰³Ru.

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The main phase transition of a membrane is attributed to conformation changes of the hydrocarbon chains constituting the lipid bilayers. The excluded volume effect, which is crucial for cooperative nature of the conformation changes, is taken into consideration by a modified dimer model. Statistical mechanics of the model is investigated rigorously by means of the transfer matrix formalism without introducing any extra simplification such as the continuum approximation. The model is found to exhibit a new type of second order phase transition which does not contain critical fluctuation: Specific heat is zero for T<T_c and is bounded by a finite value for T≥T_c. A variational evaluation of the maximum eigen-value of the transfer matrix is given for the purpose of quantitative (though approximate) analysis of the phase transition.

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Correlation of velocities of the molecules in a simulation cell is examined by devising a stochastic model of free molecular motions across cell boundary; the model is such that each molecule refreshes its velocity over time step Δτ with probability φΔτ, where φ>0. Although the correlation coefficient of velocities of a molecule and its collision partner increases with time, yet it remains at most within O(N⁻¹), where N is the number of molecules in the cell. This forms a marked contrast to the result for no refreshing process of φ=0; in case of φ=0 the correlation coefficient tends to unity as τ→∞, τ being the time measured in units of mean free time. Also, correlation coefficients of velocities at two time points τ, τ+η are examined. Suppose that φ∼O(1), N>>1 and τ>>1. If the two velocities belong to a single molecule, the coefficient is e^−(φ+θ)η+O(N⁻¹) where θ\simeq2. If they belong to different molecules, it is O(N⁻¹). A more restrictive condition τ<<N is required for these estimates to hold in case of φ=0.

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The mechanism of superconductivity in the first stage graphite-alkali metal intercalation compounds C₈M (M=K, Rb, or Cs) is investigated by the use of a method to solve the gap equation from the first principles. The observed transition temperature and anisotropy of the superconductivity can be explained well, when we consider that the three-dimensional alkali metal s-like electrons contribute to superconductivity with the aid of both the acoustic and the optic phonons in which the negatively charged carbon layers oscillate, respectively, in phase and out of phase with the positively charged alkali metal layers to give strong polar couplings with the electrons. The possibility of superconductivity in the two-dimensional graphite π-like electrons is also examined by the same method and found to be very small.

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A new type of the spatial correlation function of the structurally induced inhomogeneities of magnetic moments is introduced within the framework of the molecular field approximation. The effects of the function to the critical phenomena are discussed. The experimentally observed curvatures of the Arrott plots and the temperature dependence of the paramagnetic susceptibility in amorphous ferromagnets are satisfactorily reproduced in terms of the theory.

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Magnetization measurements on Fe_0.864Se (3c type) single crystals have been carried out around the temperature of spin axis transition (T_s=150 K). Above T_s, the material behaves as a usual ferrimagnet having the easy plane (c plane). Below T_s where the c axis is the easy direction, the observed magnetization curves have some resemblance to those of metamagnets: A sudden increase of magnetization occurs at a certain value of the applied field (10³∼10⁴ Oe) depending upon the field direction and the temperature. The hysteresis loop takes a constricted form with very small remanence (<5% of the saturation value). The composition range where these anomalies are observed is extremely narrow. The process of magnetization below T_s is described as a field-induced first-order magnetic transition of the system of antiferromagnetically coupled regions. The origin of such regions is also discussed.

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Firstly, the magnetic phase diagram of the quasi-one-dimensional antiferromagnet (CH₃)₃NHMnCl₃·2H₂O for the fields applied parallel to the magnetic easy and intermediate axes is studied by means of heat capacity measurements. The observed field dependence of the ordering temperature is reproduced satisfactorily by the theory similar to that developed in our previous study on (CH₃)₄NMnCl₃ (TMMC). A brief discussion is also given on the experimental phase diagram of (CH₃)₃NHMnBr₃·2H₂O. Secondly, measurements of adiabatic magnetization cooling are performed for both compounds. It is found that the cooling occurs in the paramagnetic phase as well as in the antiferromagnetic phase.

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A new theory of the magnetism at finite temperatures which takes account of the local environment effect and can describe the glass-like phase (GLP) is formulated by using the functional integral method combined with the method of the distribution function. The theory is applied to the NiMn alloy, and the local magnetic moments in various environments are calculated as the functions of the temperature, the concentration and the atomic short range order. The Curie temperature and the freezing temperature are also obtained. Anomalous behaviours such as the temperature-induced magnetization and the strongly variable magnetization with the atomic ordering in NiMn are explained for the first time by the present theory of itinerant-electron systems.

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The effects of spatial fluctuations of impurity potentials on the magnetic interaction between a pair of donors are investigated in a system of two electrons interacting with a short-range repulsive force in the conduction band of a semiconductor containing two donor-type impurities. The potential wells due to these impurities are assumed to be deep enough to have one and only one bound state. The potential fluctuations are found to assist the magnetization of the ground state of the impurity pair, for which the interaction is repulsive.

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A simple form of transition metal model potential has been used to investigate the phonon spectra of niobium. Most of the anomalies in the phonon dispersion curves have been explained by the present model potential approach. The results thus obtained show a fairly good agreement with the experimental ones. The binding energy also agrees with the available experimental results.

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According to the non muffin-tin theory of the APW method, the potential due to periodic array of multipoles is given in rapidly convergent forms, separately for the regions inside and outside the muffin-tin spheres. The present results improve Rudge’s treatment on the same problem, which is awkward to handle due to its slow convergence and its inclusion of various terms with no resultant. The numerical values are given also for the hexagonal close-packed structure.

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We study the satellite near 3p-threshold in the resonant photoemission associated with the two-d-hole bound state in metals such as copper. The satellite is considered to originate from Auger transition resulting from the super Coster-Kronig decay of the 3p-core hole. The copper density of states is reproduced by a two hybridized 3d-4s-band model. We test the influence of the hybridization upon the photoelectron spectrum and we discuss the importance of the s-screening around the d-hole pair with respect to the satellite position and relative intensity of the satellite and the Auger emission. Comparison is made with available experimental data.

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A general expression for the Grüneisen function has been developed for ionic crystals employing the ion-ion interaction theory. The developed expression has been utilized to evaluate the values in the frame work of Born-Mayer potential energy function. It has been found that the calculated values of γ are in satisfactory agreement with the experimental values and are better in comparision to the other theoretical values.

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ZnTe which exhibits a few characteristic resistance changes under pressure has been studied in regard of volume change by a recently confirmed manganin coil method. Relatively large volume reductions are observed at 90 and 120 kbar corresponding to the abrupt resistance changes. A small volume reduction found at 70 kbar may suggest an existence of an isostructural transition.

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An analysis of the cohesive and thermophysical properties of the halides of copper and thallium has been performed by modifying Hafemeister and Flygare (MHF) potential to include the three-body interaction effects. This modified HF potential is found to yield a better description of the above properties than those obtained by earlier workers. The universality of the present MHF potential with the importance of the significant role of the three-body and van der Waals interactions is also emphasised.

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Optically detected magnetic resonance experiments provide evidence for creation of defects (dangling bond centres) by prolonged laser light irradiation in hydrogenated amorphous silicon.

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The possibility of formation of electron-hole droplets and of inducing transition to mixed valence state in SmS at low temperatures and at high carrier densities produced by high intensity laser beam is analyzed. Experimental methods for detection of these transitions are outlined.

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The hot electron effect at low lattice temperatures 1≤T≤30 K is studied on the assumption that, in addition to the phonon scattering and some residual scattering independent of T, there is an unknown mechanism which limits the electron mobility such that μ⁻¹(T_e, T)=μ_RES⁻¹+μ_ph⁻¹(T_e, T)+μ_?⁻¹(T_e), where T_e is the electron temperature. μ_?⁻¹(T_e) is determined by requiring that μ⁻¹(T_e, T) reproduces the measured low field mobility. The field dependence of μ(T_e, T) is deduced from the usual energy balance consideration and it is concluded that the dependence can provide a crucial test for the existence of μ_?⁻¹(T_e) for it should be noticeably weaker if there were no such unknown mechanism.

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The magnetic-nonmagnetic transition and the charge transfer instability in the two-electrons two-impurities system in semiconductors is studied by an exactly soluble one-dimensional model. The model is characterized by the on-site Coulomb repulsion and the linear electron-lattice coupling at the impurity sites and the electron transfer energy, in addition to the distance between the impurities and the local potential depth. The ground state adiabatic potential energy surfaces are calculated exactly and the phase boundaries for the magnetic-nonmagnetic transition as well as the charge symmetric-asymmetric transition are obtained. This model exhibits the features of Toyozawa’s two-electrons two-sites model in the case of the nearest neighbor pair and Anderson’s negative U system in the limit of infinitely distant pair.

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Brillouin scattering from A-surface exciton polaritons in a prism-air-CdS configuration, i.e. the Otto geometry, is theoretically analysed. The acoustic modes which participate in the scattering are written in the form correct for a thick plate of CdS. Two light-scattering mechanisms, namely, the surface corrugation and deformation coupling effects, are taken into account in deriving optical fields which satisfy the acousto-optically driven wave equation and the appropriate boundary conditions. The numerical estimates indicate that the Brilouin signal should be detectable and that the dispersion relation of surface exciton polaritons can be measured. Moreover, it is expected that an experiment would provide information about surface exciton-acoustic phonon interactions.

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The dynamics of excitonic polaritons initially photoexcited in the upper branch have been investigated by observing the transient induced absorption from the excitonic polariton to excitonic molecule state in CuCl. Upper branch polaritons generated by picosecond tunable laser pulses are quickly scattered to the lower branch. Lower branch polaritons are relaxed within the lower branch by the LA phonon emission undergoing the frequent mutual collisions and finally annihilated radiatively. As a result of these relaxation processes the bottleneck effect is clearly observed. The observed mean lifetime of polaritons dependent on the sample thickness supports the interpretation of the lifetime of exciton based on the polariton concept.

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The structural phase transition in KCdF₃ is investigated by analysing EPR spectra of Gd³⁺ centres with Cd²⁺ vacancies on nearest neighbour lattice sites. Temperature and field-direction dependence of the spectra shows occurrence of successive phase transitions at around 485 and 471 K. In the second phase 471 K<T<485 K, the field-direction dependence obtained in this experiment is not consistent with that expected from the condensation of the M₃^z phonon mode which was previously reported. The experimental results are interpreted by a model that these phase transitions are due to the condensation of the alternate rotations around two cubic axes at 485 K and around another axis at 471 K.

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The dielectric constant, specific heat and thermal expansion of CsHSeO₄ were measured as functions of temperature, and X-ray examination was also made. It was found that CsHSeO₄ undergoes a phase transition at 128°C. The crystal at room temperature is monoclinic with a space group P2/c. The transition entropy was estimated from the specific heat to be ΔS=16.1 J·mol⁻¹·deg⁻¹.

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The phase transitions in {N(CH₃)₄}₂XBr₄ (X: Zn, Co, Cu) were stuided by dielectric measurements. A phase transition which accompanied with a break on the dielectric constant vs temperature curve was found at 13.5°C and 13.8°C for {N(CH₃)₄}₂ZnBr₄ and {N(CH₃)₄}₂CoBr₄, respectively. In {N(CH₃)₄}₂CuBr₄ three phase transitions were found at −1°C, −31°C, and −36°C on cooling. In the temperature range between −31°C and −36°C the crystal shows ferroelectricity along the pseudo-hexagonal c-direction. The spontaneous polarization is about 7×10⁻⁸ C cm⁻².

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An improved theory of the surface potential decay in trap free dielectrics is presented. The effect of relaxation time on surface charge decay characteristics (SCDC) is theoretically investigated. A condition for minimum surface potential required to observe transit time from SCDC is obtained.

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Plastic deformation by mechanical twinning with (001) twin plane has been observed in the b-plate of CsHSO₄ single crystals at room temperature. A parallelogram-shaped hysteresis loop is found between the external shear stress and the deformation angle of the crystal plate. The maximum deformation angle is found to be 24° which is very close to 2(β−90°), where β=101.51° is the monoclinic angle of the crystal lattice. A microscopic model based on the crystal structure for the twin structure is proposed.

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Detailed measurements of the resistivity and the Hall coefficient have been made on high-quality single crystals of 2H metallic transition-metal dichalcogenides between 4.2 K and 300 K, in order to investigate the carrier scattering mechanisms in a CDW system. The resistivity of 2H-NbS₂, which has no CDW transition, shows normal behavior. On the other hand, in 2H-TaSe₂ which has the highest CDW transition temperature (T_o=122 K) of 2H family, several anomalous features are observed. The temperature dependence of the resistivity in 2H-TaSe₂ is ∼T⁵(T<15 K), ∼T²(30 K<T<100 K) and AT+B(T>T_o). The results were analyzed by including a “new” scattering mechanism due to phase fluctuations of the CDW (electron-phason scattering, phase disorder scattering). The analysis suggests that McMillan’s phonon entropy model is more appropriate in 2H-TaSe₂ than the conventional model.

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The magnetoresistance and Hall coefficient in the charge-density-wave (CDW) state of 2H-NbSe₂ and 2H-TaSe₂ have been measured at low temperatures in magnetic fields up to 150 kOe, using high-quality single crystals. The results on these two compounds have been compared with those on 2H-NbS₂ which has no CDW transition. By the comparison, several anomalous features in the CDW systems (2H-NbSe₂ and -TaSe₂) have been made clear: 1) The magnetoresistance is relatively large and exhibits a linear dependence on magnetic field. 2) The Hall coefficient shows a strong field dependence including a minimum. We consider that the observed behaviors in the CDW systems may be explained by reconstruction of the Fermi surface in the CDW state and magnetic breakdown through the CDW gaps.

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Using an effective Hamiltonian to describe the dynamics of the center coordinates of the cyclotron motion, the structure of the tail states of the Landau subbands is discussed. Eigenvalue problem is explicitly solved in the case of a single Gaussian-type potential. The eigenfunctions do not depend on the range of the potential while the eigenvalues do. The contribution of the tail states to the dynamical conductivity is shown to be proportional to D(E_F)²ω² In ω in the low frequency limit with D(E_F) the density of states at the Fermi energy E_F.

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The response to an applied electric field of charged edge dislocation and surrounding charge cloud system is calculated for the case that the cloud is composed of two species of movable charged point defects. It is shown that at low frequency region the charged dislocation senses the unscreened field and the coefficient of the converse piezo-electric effect does not coincide with that of the direct effect.

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The temperature dependence of the emission spectrum of europium-activated NaCl, KCl, RbCl, KBr, KI, and RbBr has been measured in the temperature range 77–600 K. From these data the activation energy corresponding to the thermal quenching of the Eu-luminescence, as well as the vibrational frequency interacting with the center in its excited state have been determined for each crystal.

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The explicit formulae applicable to ARXPS from deep core orbitals in a fixed sample are given in the short-range order theory. Also the formulae which are directly applicable to the calculation of ARXPS intensity irradiated by unpolarized X-ray are derived in this theoretical framework. Also the discussion is given for the different behavior of ARXPS intensity irradiated by linearly polarized and unpolarized X-ray.

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The ordered structure of 2nd stage alkali metal graphite intercalated compound C₂₄Rb has been investigated with X-ray diffraction. Below 165 K, we observed satellite reflections around each fundamental Bragg reflections due to configurational ordering of Rb⁺ ions. In addition, we also found weak sub-satellite reflections. These sub-satellites, as well as the main satellites, are indexed as superlattice reflections when we assign a large (9×9) unit cell. Based on the (9×9) unit cell and on the assumption of registered configuration of Rb⁺ ions, we could construct a plausible model structure of C₂₄Rb at 150 K. The observed characteristics of the experiments are qualitatively reproduced by the present model.

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A shape for pressure-broadened lines applicable from the central region to the far wings is obtained by combining the Lorentz shape with the statistical shape. This line shape is compared with the Varanasi et al.’s super-Lorentz shape with the same values for intensity and line width. The measured transmittances of NO and CO₂-broadened HCl lines are well represented by this line shape.

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The generalized expression for the ponderomotive force acting on a plasma in which a electromagnetic wave is excited is obtained from the hydrodynamical equations. The ponderomotive force is calculated from the time-averaged stress tensor with the generalized pressure tensor, which includes the higher order effect of high-frequency fields.

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The improvement of absorption and hydrodynamic efficiency was experimentally investigated by using a double-foil target with a pinhole for laser beam. The behavior of the accelerated target is reasonably consistent with a cannonballx-acceleration model. The absorption coefficient and the hydrodynamic efficiency increased by factors of 14 and 7, respectively, in comparison with a single foil target under the same irradiation condition.

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