Low-lying excited levels in ²⁰⁰Hg were investigated with a Ge(Li) gamma-ray spectrometer and with an internal conversion coefficient spectrometer. The spin and parity 2⁺ of the 1028.7-keV third excited level were confirmed, based on the internal conversion coefficient and K/L ratio of the transition from this level to the first excited 2⁺ state. Several new lines were found. A revised decay scheme was proposed. The experimental results showed that the nuclear structure of this nucleus can be understood fairly well with a model of two-proton holes coupled to harmonic surface vibrations.

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Glauber’s one-dimensional Ising model is extended to the case of spin S=1 by developing the time-dependent constant coupling approximation. It is shown that there exist two relaxation times. The one increases monotonically with decreasing temperature and diverges to infinity at T=0°K, but the other is very small and scarcely varies with temperature. The dynamical susceptibility is also calculated, which coincides with the rigorous one in static case.

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When crystals are distorted periodically by a vibrating force, transitions take place among nuclear Zeeman levels of Δm=±2 in the rotating frame. This excitation is observed as the reduction in relaxation times of spin-locked magnetization. Unlike ultrasonic excitation in the laboratory frame, the acoustic frequency is low (2_γH₁⁄2π), and this fact, together with a high sensitivity to a strain, enables one to determine the electric field gradient-elastic tensors s accurately. These effects have been demonstrated for Na in NaCl single crystals. Measurements for several orientations of the force and the external magnetic field have yielded S₁₁=(2.8±0.3)×10¹⁵ statcoul/cm³ and S₄₄=−(0.81±0.08)×10¹⁵ statcoul/cm³. These values are explained by a consideration of overlap effects in addition to ionic point-charges.

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Magnetic property of CrSb₂ having marcasite structure was investigated by means of magnetic, X-ray and neutron diffractions, specific heat and electrical resistivity measurements. The magnetic susceptibility of CrSb₂ showed a maximum at about 550°K and it seems to be antiferromagnetic with a negative paramagnetic Curie point. From neutron diffraction and specific heat measurements, however, it was found that CrSb₂ has no antiferromagnetic spin ordering. The resistivity is semiconductive with two activation energies, 0.14 eV and 0.07 eV below and above 200°K, respectively. Basing on a covalent crystal model, an explanation on the magnetic and the electrical properties were given: that is, the ground state has no magnetic moment (S=0), but the excited state is paramagnetic (S=1) with the energy gap of 0.07 eV from the ground state.

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The magnetoconductivity of metals with magnetic breakdown is calculated quantum mechanically. The calculations are done for the weak scattering limit, based on a rigorous treatment of periodic potentials. When the scattering due to impurities is weak and the level broadening is negligibly small, the transverse magnetoconductivity can be described by the “intraband” and “interband” processes in the “magnetic energy band”. As an application of the obtained formulas the transverse magnetoconductivity is calculated on a simple model for the periodic potential—one-dimensional weak cosine potential. The results of our calculations show rather complicated oscillatory behaviors which come from the phase coherence between orbits.

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The approximate energy bands for Cr, Mo and W metals are built up from the energy bands for the paramagnetic Cr metal, by taking into account the spin-orbit interaction. The effect of the spin-orbit interaction to the paramagnetic susceptibilities for 3d, 4d and 5d b.c.c. transition metals and their alloys are investigated. The spin paramagnetic susceptibilities χ_s and the orbital paramagnetic susceptibilities χ_orb for 3d metals and their alloys are the largest, followed by those for 4d and 5d metals and their alloys in that order, and the mixed contribution due to the spin and orbital angular momentums, χ_so, is negligibly small. The calculated paramagnetic susceptibilities agree with the results of the experiments, by adopting the reasonable values of a molecular field coefficient. The method to analyze the paramagnetic susceptibilities for the alloys composed of 3d and 4d, 4d and 5d or 3d and 5d transition metals is suggested and the experimental results for V–Nb and Nb–Ta alloys are analyzed.

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Phonon scattering by dislocations at liquid helium temperature has been studied by measuring the thermal conductivity of Cu-15 at % Al alloy crystals deformed by various amounts. Curves of lattice thermal conductivity vs. temperature plotted in log-log scale are concave upwards in the temperature range between 1.6∼4.2°K. These experimental data cannot be described by the scattering of phonons by the static strain field around dislocations through anharmonicity. The result is interpreted by assuming resonance scattering due to vibrating edge dislocations in their Cottrell atmospheres in addition to the scattering due to electron-phonon interaction.

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For the trapped Radicals A, B, C, D and E, g- and ³³S hf-tensor parameters are determined. Radicals A, B and C have already been identified as SSO₂⁻, SSO⁻ and SSO₃⁻ respectively. For Radical A g-tensor parameters are different from that reported, and these support the model more adequately. Optical absorption of this radical is shown. Observation of hf-interaction with central ³³S of Radical B confirms the reported model. For Radical C at least two sets of nonequivalent ³³S hf-satellites are observed, then the identification of SSO₃⁻ for this radical becomes more reliable. A feature of thermal decomposition of this radical into others is shown. Radical D which has the same chemical formula as SSO⁻ but has a conformation different from Radical B in the crystal lattice is found.

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Three species of radicals were observed. One of these was already identified as HN₃\dotCHCOO⁻ by Ovenall et al. and by Blinc et al.. One of the other species, which appears as a triplet with an intensity ratio of 1:2:1, is identified as \dotCH₂COO⁻. The principal values of A- and g-tensor of the radical are determined to be 25.1, 19.6 and 16.7 gauss and 1.9994, 1.9999 and 2.0009, respectively. From the temperature dependence of the spectra, it is concluded that the two protons in the \dotCH₂COO⁻ exchange their sites with each other through a rotation of the \dotCH₂ group about the C–C_N bond.

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A phase transition in ferroelectric NaNO₂ is found at −95°C from precise measurements of thermal expansion and low frequency dielectric constant. At this transition temperature, slight break exists both in dielectric constant vs. temperature and in thermal expansion vs. temperature curves. Below the transition temperature, the room temperature ferroelectric phase transforms to a high pressure phase which exists above 8 kbar at room temperature.

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Acoustic domains in semiconducting CdS are studied by Brillouin scattering measurements at room temperature. Time-variations, spatial distributions and frequency spectra of the generated acoustic flux are revealed experimentally. The propagation of the acoustic flux is separated into regions of exponential growth, steady-state saturation and anomalous damping. Such flux behaviors are not accompanied by the corresponding change of the sample current. The frequency spectra range from 200 to 1200 MHz and change slightly during propagation. Linear acoustic gains in this frequency range agree fairly-well with the theoretical curve of White. However, the acoustoelectric phenomena cannot be explained by these low frequency acoustic waves only. Thus, Brillouin scattering is not always valid to examine the acoustoelectric instabilities because of its frequency limitation (\simeq2.8 GHz).

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Giant quantum oscillations of the magneto-acoustic attenuation in arsenic have been studied for the 140 Mc/sec longitudinal wave and in the magnetic fields up to 93 kG. The observed attenuation peaks are spike shaped with spin splittings. The energy surface parameters and spin splitting parameters for holes on the γ-neck were determined from the attenuation peaks. The splitting above mentioned shows that for the field which is parallel to the trigonal axis, the effective g-factor is found to be 75. The line shape of the giant quantum attenuation peak has been interpreted in terms of the nonparabolic energy band model and it revealed the hole-mass character typical of the saddle point on the γ-neck.

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Dielectric constant of single crystals of NiO, both pure and containing small amounts of Li, has been measured in the frequency range from 10² to 2.4×10¹⁰ Hz as a function of temperature between 150 and 450°K. At low temperatures the dielectric constant has a constant value independent of temperature, while at high temperatures it increases strongly with arising temperature. This abrupt increase is more conspicuous for highly doped specimens and at lower frequency. The strongly increasing capacitance is considered to be due to a polarization caused by the space charge at the specimen-electrode interface. The apparent dielectric constant can be interpreted by an equivalent circuit somewhat similar to that of rectifier.

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Ferroelectric hysteresis loops are observed in the mixed crystals of Ca₂Sr(C₂H₅CO₂)_6(1−x)·(CH₃CO₂)_6x in the range of 0≤x≤0.17. The Curie temperature decreases remarkably with increasing CH₃CO₂ concentration according to the relation of T_c(x)=T_c(0)−600x(°C), where T_c(x) is the Curie temperature at x.

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A theory of X-ray diffractions from disordered crystals, which are composed of the polymer molecules of helical structures, is developed. This theory gives the relationships between various disorders in polymer crystals and the diffuse streak diffraction patterns on layer lines as well as Laue-Bragg reflections. The results derived here include those given by Clark and Muus in 1962.

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Phase stability relations among four hexagonal perovskite-like structures as well as the cubic perovskite structure have been studied for several oxides (BaMnO₃ and SrMnO₃) and fluorides (CsMnF₃, RbNiF₃ and TlNiF₃) at high pressure. A series of high pressure transformations are found to occur in the order of the packing sequence along the hexagonal c axis (or cubic 111 axis) of (ab), (ababcbcac), (abac), (abcacb) and (abc) with increasing pressure. This order is corresponding with the increasing order of the proportion of the cubic close-packed layers in the hexagonal close-packed structure. It is suggested that the tolerance factor of the perovskite structure and the Coulomb repulsive force play an important role in determining the crystal structure and its order in the series of phase transformations at high pressure.

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The transient formation and decay of F centers in KCl crystals have been studied using a pulsed electron beam from a linear accelerator. The electron pulse has a 30 ns half width at 60 MeV and the maximum peak current is 1.2 amp. In “as received” crystals F center formation is of the fast type which takes place in very short time less than the pulse width and generated F centers bleach partially within ∼40 ns, probably due to the tunneling annihilation with H centers. In “irradiated” crystals which are discolored and bleached with white light, the F center formation consists of the fast and slow types. The slow type formation has a time constant of 0.60±0.02 μs at 80°K which is the same as the decay time of the F center luminescence. The slow type formation is, therefore, considered to take place when an electron is captured by an anion vacancy through the first excited state of the F center.

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Absorption spectra of KI containing high concentrations of Ga⁺ and In⁺ impurity ions are obtained at 2°K. New absorption bands which are due to the (Ga⁺)₂ and (In⁺)₂ paired-ion centers are observed at 4.04 and 4.51 eV in KI:Ga and at 3.75 and 4.25 eV in KI:In. The low-energy bands A′ are unambiguously related to the A band and the high-energy bands C′ to the C band. Trials have been made to understand the electronic structure of the paired-ion center in terms of the electronic structure of the single-ion center. The paired-ion-center absorption bands related to the C band are unambiguously assigned as follows: the C′ band is due to the transition ¹∑_g⁺(¹A_1g)→¹∑_u⁺(¹T_1u), and the band due to the transition ¹∑_g⁺(¹A_1g)→¹Π_u(¹T_1u) under- lies the C band. As for the paired-ion-center absorption bands related to the A band, two possible assignments are suggested.

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The absorption measurements were made on thin films of solid solutions of alkali chlorides at room temperature. The differences in the spectra of NaCl, KCl, and RbCl are discussed in connection with the nature of the alkali metals. From the measurements in KCl–NaCl and KCl–RbCl, additional evidences were obtained for the assignment of the peaks at 20.3 eV and 21.5 eV in KCl being due to the transitions from K⁺ 3p level. The peaks at 11.4 eV and at 12.3 eV in NaCl are proposed to be attributed to Na⁺ ion through the results obtained in KCl–NaCl system. These peaks in NaCl were found to behave consistently also in the system NaCl–NaBr.

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The Stark effect in CH₄ which has no permanent dipole moment in the ground vibrational state is observed on one component line at 2947.802 cm⁻¹ of the P(7) line in the ν₃ band by a magnetically tuned infrared maser. The effect is interpreted on the basis of the second-order induced dipole moment in the degenerate vibrational state which has the F₂ symmetry. The magnitude of the induced dipole moment of CH₄ in the ν₃ vibrational mode is evaluated from the observed Stark effect.

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On the basis of the Klimontovich equation, the longitudinal dielectric permeability \ ildeε is obtained in the form
(Remark: Graphics omitted.)
in which, for instances, ⟨\hata⟩=⟨\hata(k,ω;k,ω)⟩, (Remark: Graphics omitted.). Here the quantity \hata(kω;k′ω′) is represented in terms of the microscopic electric field and the microscopic distribution function; the symbol ⟨ ⟩ denotes the ensemble average with respect to initial conditions; (Remark: Graphics omitted.) or (Remark: Graphics omitted.) means the third or fourth-order correlation part in the average of the product of appointed \hata’s, respectively. Some reduction to approximate results are given.

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Interchange stability and drift motion of a plasma losing unsteadily are analysed in a low β limiting case with the use of ideal hydromagnetic equations. The m-th mode of radial displacement δr_m of the plasma boundary is subject to the equation δ\ddotr_m−(S⁄V)δ\dotr_m+m(P⁄V)δr_m=0, where the dots indicate the time derivatives and the coefficients are some averages of the state of the flow along the entire line of force. The reactive force is due to the Corioli’s force on the flowing plasma within a moving flux tube, and the potential force is due to the plasma pressure and the centrifugal force of the flow. Solutions of the equation show that the system is stabilized by the plasma outside the ends, in good agreement with experiments.

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Asymptotic analysis of the surface displacement integrals obtained in the solution of the three-dimensional problem of waves due to a surface pressure F(x,y)e^iwtH(t) [where H(t)=0 for t≤0 and H(t)=1 for t>0] in water of finite depth is carried out for large distances and times by the method of stationary phase. The steady state solution found here for a large class of functions F(x,y) by a direct passage to the limit t→∞, is evaluated in exact terms. Some particular spatial pressure distributions over elliptic regions together with some characteristic features of the wave motion are discussed. An illustration of the directional variation of the waves is added.

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Ultrasonic velocity has been measured in three different carbon steels in their commercially received and annealed conditions and in two of them in quenched condition by total reflection technique at room temperature and at 5 Mc. The elastic constants of these samples have been calculated by known relations in velocities and elastic constants, and their magnitude variation has been discussed.

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