It is proved that some integrable models are gauge equivalent to the sine-Gordon and Pohlmeyer-Lund-Regge models. The Zakharov-Shabat representations are recovered for these models.

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Stability of the dromion solution of the Davey-Stewartson equations is investigated numerically. Propagation of dromions is found to be stable in a Lyapunov sense. Collisions of two one-dromions are also examined. It is observed that the collision process is inelastic and the initial two dromions break into four pulses after the collision.

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In CP violation measurements in asymmetric B-factory experiments, a determination of the B flavor of the neutral B mesons is necessary. A new method to this purpose using only three vectors of charged particles has been developed. This method (weighted charge method) does not require either lepton identification or charged-kaon identification. The tagging efficiency, probability for incorrect tagging, and effective tagging efficiency of this method are 43.1, 18.3, and 17.3%, respectively.

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A new method to estimate the fast-neutron fluence of the Hiroshima atomic bomb is proposed. ⁶³Ni produced by the ⁶³Cu(n, p)⁶³Ni reaction provides a unique measure by which to estimate the fast-neutron fluence of the Hiroshima/Nagasaki atomic bombs, because the half-life of ⁶³Ni is 100 years and 70% of the ⁶³Ni produced in a copper piece presently exists after 50 years. Using the neutron spectrum given in DS86 and the estimated cross section, we found that a piece of copper of about 10 g which was exposed at a point around 100 m from the hypocenter gives a measurable amount of ⁶³Ni using a low-background liquid scintillation counter. For the measurement of ⁶³Ni, accelerator mass spectrometry also seems to be applicable.

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On the basis of soft-X ray diagnostics, it is shown that the role of the edge fast electrons in the reversed-field pinch (RFP) dynamo mechanism is insignificant in the early phase of a discharge in the STE-2 RFP. In the high-fill-pressure region, this is also the case even with the current maximum phase. The pressure dependence of the edge magnetic fluctuations is possibly different from the expected dominance of the MHD dynamo activity in the high-pressure regime, indicating the importance of direct measurement of the phase relation between velocity and magnetic field fluctuations.

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By combining the Padé approximant and the coherent-anomaly method, the equation of state in the liquid region for a hard-core system is obtained from the virial series expansion. The effective exclusive volume is found to be equal to the volume of the hard core. The fact that this volume is less than the close-packing volume suggests the existence of the liquid-solid phase transition (the Alder transition) in two- and three-dimensional hard-core systems.

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A constant-volume molecular dynamics calculation has been performed for a cubic yttria-stabilized zirconia (Y₂O₃)_c(ZrO₂)_1-c, where Y layers and Zr layers are alternately accumulated to form a superlattice. A considerable enhancement of the diffusion of oxygen ions was observed at the composition c=0.33, at which the diffusion coefficient in the superlattice is about three times larger than the case of a random distribution of Y ions.

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Single-crystal C₆₀ films were successfully grown on GaAs (111) A surface by MBE. The C₆₀ film was investigated by in situ observation of RHEED. C₆₀ molecules grew into a monolayer film with the close-packing fcc configuration. The film was confirmed by X-ray diffraction study to be of high-quality (111) oriented crystal. The results may be put single crystal C₆₀ on semiconductor into use for many devices.

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Transport and magnetic properties have been studied for BaCo_1-xNi_xS₂ with a two-dimensional electron system which exhibits the Mott transition upon varying x. Various anomalous behaviors of these properties can be considered to be similar to those of high-T_c Cu oxides, indicating that Cu-oxides are not the only compounds with the well-known “anomalous normal state”.

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We investigated the formation of three-dimensional (3D) magnetic ordering in a quasi-1D ferromagnetic chain system CoNb₂O₆ by neutron scattering. With decreasing temperature below T₁-- 3, K in the helical magnetic phase, anomalous broadening of magnetic satellite reflections was observed in the directions perpendicular to the 1D magnetic chain, with a rapid change in the propagation wave number of helical magnetic ordering. Furthermore, in the antiferromagnetic phase below T₂-- 1.9, K, CoNb₂O₆ exhibits a pronounced 2D magnetic character. These features result from the competition between interchain exchange interaction and Co²⁺ single-ion anisotropy in this compound.

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Inelastic neutron scattering in the SDW state of Cr at 54, K revealed a complex dynamical structure in Q. Magnetic scattering centered at the commensurate wave vector of (1 0 0) is observed in addition to the scattering centered at the incommensurate wave vector of SDW. Integrated intensities, ∫ , d Qχ''( Q, , ω ), for commensurate scattering increase linearly with the excitation energy, but those of the incommensurate scattering saturate at 15--20, meV. The crossover from the coexisting state of the commensurate and incommensurate spin fluctuations to the state in which the commensurate scattering is dominant, occurs at 30--40, meV. This new result questions the validity of a simple linear spin-wave approximation in the SDW state of Cr.

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We have investigated the antiferromagnetic nuclear magnetic resonance (AFNR) of ⁵¹V in perovskites LaVO₃ and YVO₃ under zero external magnetic field. In LaVO₃, two distinct resonance lines are observed around 261.90± 0.05, MHz and 268.98± 0.05, MHz at 4.2, K. These signals are associated with the inequivalent ⁵¹V sites generated by the structural transition at T_N. The Larmor frequencies at the inequivalent sites are found to show different temperature dependences. This clearly indicates that the temperature dependence of the sublattice magnetization is different for each site, and may be related to the anomalous diamagnetism of this compound. The resonance line is observed around 278.8± 0.1, MHz at 4.2, K in YVO₃. The hyperfine coupling constants of both substances are also estimated.

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By using stochastic theory, we clarified the difference between coherent and incoherent two-pulse photon echoes from the viewpoint of non-Markovian behavior. At the slow modulation limit, the incoherent two-pulse echo was found to exhibit an exp, (-ct²) dependence which is in contrast with the exp, (-ct³) dependence in the coherent two-pulse echo.

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The W_∞ -algebra is constructed from the Lax operator of the quantum Calogero model. The “generalized” Lax equations for the W-operators are explicitly shown. Due to this finding, all the verifications are extremely simplified. Algebraic construction of the eigenstates of the model is also shown.

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We introduce an approximation scheme where the Bethe ansatz is applied to non-integrable systems: the many-body S matrix is approximated by a product of two-body S matrices. We call this method Bethe-ansatz approximation (BAA). We apply the BAA to the S=1 antiferromagnetic bilinear-biquadratic quantum spin chain. The model contains a parameter β, the ratio of the biquadratic coupling to the bilinear coupling. Except for β =-∞, ± 1, the system is non-integrable. Varying β, we performed BAA calculation of the ground-state energy as a function of the total magnetization. Comparison with the numerical diagonalization shows a considerable efficiency of the BAA up to medium or more particle density.

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Effects of a bottleneck in a linear trafficway is investigated using a simple cellular automaton model. Introducing a blockage site which transmit cars at some transmission probability into the rule-184 cellular automaton, we observe three different phases with increasing car concentration: Besides the free phase and the jam phase, which exist already in the pure rule-184 model, the mixed phase of these two appears at intermediate concentration with well-defined phase boundaries. This mixed phase, where cars pile up behind the blockage to form a jam region, is characterized by a constant flow. In the thermodynamic limit, we obtain the exact expressions for several characteristic quantities in terms of the car density and the transmission rate. These quantities depend strongly on the system size at the phase boundaries; We analyse these finite size effects based on the finite-size scaling.

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An effective analysis for the static and the dynamic properties of an assembly of classical anharmonic oscillators moving in the double Morse potential (DMP) is made in the framework of the molecular field approximation and the linear response theory. By using the effective (trial) potential V₀(x)=Ax⁴+Bx² with the temperature-dependent coefficients A and B, some characteristic effects of the higher anharmonicities in DMP are quantitatively considered. The present method offers an extension of the self-consistent Einstein theory, which enables us to make discussions on the static and the dynamic properties of the system from the unified mechanical point of view whether the relevant potential is of single- or of double-minimum.

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We study the scaling behaviour of the diameter s of coalescing particles obeying the nonlinear conservation law: s^Δ=s₁^Δ+s₂^Δ in the coalescing random walker model with injection where s₁ and s₂ are the diameters of two particles before collision. The dynamic exponent z of the mean diameter s and the scaling exponent τ' of the cumulative size distribution are obtained by computer simulation. The exponents z and τ' depend strongly on the diameter exponent Δ. The scaling exponents z and τ' are given by z=3/2Δ and τ'=Δ/3 for Δ≤ 1.0. For Δ≥ 2.0, the exponents z and τ' are given by the mean-field values z=1 and τ'=1/2. At the upper critical value Δ_c=2.0, the scaling changes to the mean-field behaviour. For Δ≤ 1.0, the scaling relation (Δ-τ ')^-1=z is satisfied. It is shown that the diameter-size distribution n_s(t) satisfies the dynamic scaling form n_s(t)≈ s^{-(τ '+1)}f(s/t^z).

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Spin-1 XXZ chain in a magnetic field (\Hta=∑ _i(S_i^xS^x_I+1+S_i^yS^y_i+1+λ S_i^zS^z_i+1)-h∑ _iS_i^z) for -1<λ <1 is studied by the exact diagonalization using the Lanczös method up to 16 sites, and the exponents of the correlation functions, η _x and η _z, for the partially magnetized state is calculated applying the conformal field theory to the obtained data. We find that the dependence of the exponent on the magnetization m changes at λ -- 0, and this is consistent with the conjecture that the transition from the massless XY phase to the massive Haldane phase takes place at λ -- 0. The critical value λ _{c₁} is estimated as 0.068± 0.003 from the criterion η _x=1/4 at λ _{c₁}. The values of the exponent in the two limiting cases m→ 0 and m→ 1 are discussed.

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The effects of boronization on impurities, using a boron-trimethyl gas combined with helium glow discharge, are investigated in a reversed field pinch (RFP) device. After boronization, total pressure and partial ones of hydrogen and water decrease with the smaller pressure rise of hydrocarbons. From the surface analysis, we find the production of boron/carbon mixed layers (-- 40, nm thick) with metal impurities. With this conditioning, we can suppress the large increase in the plasma density. The ohmic and radiated powers in addition to impurity line intensities (especially near the plasma edge) decrease. Radial profile of soft X-ray intensity, which is higher than that before conditioning, shows somewhat broadening. The main discharges using this gas as a simple conditioning can cause the similar effects on plasma behavior.

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2-1/2 dimensional electrostatic particle simulations are performed on ion cyclotron oscillations driven by applying a positive potential to a small electrode in a magnetized collisionless plasma. Ion and electron motions are found to be synchronized with two-dimensional potential oscillations, being consistent with the Sato-Hatakeyama model of “potential-driven” ion cyclotron oscillations. A frequency deviation from the ion cyclotron frequency is explained by introducing a non-uniform electric field across magnetic field lines.

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Hot spots in a dense plasma focus are investigated with a time-resolved and filtered pinhole camera system through Ar K-lines emission. A Moire Schlieren technique is used to observe the macroscopic plasma behavior conjunctly. The hot spots are generated at the disruption of the plasma column with growth of macroscopic instabilities. At the disrupted regions, the hot spots appear and emit intense K-lines of argon approximately for 15 ns. A spatial distribution of Ar K-line emission is quantitatively obtained using the pinhole camera system. The maximum intensity, -- 9.8× 10¹¹, _{-50%}^{+170%} (photons/(s· mm²· (mrad)²· 0.01%BW)) is observed when 6% of argon is added to the 4 Torr hydrogen.

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By the use of position vectors and Ising spin, model Hamiltonians for several common stacked crystals are introduced in the light of the stacking sequences. Due to the stacking sequences each metal atom resides in one of a number of physical equivalent positions per lattice point in a stacking layer. Introducing position vectors which point to respective metal atoms in the stacking layers, the common structures along the stacking sequence are represented by the way in which the position vectors rotate. Ising spin is employed to describe the difference of rotation angle between the position vectors residing in nearest neighboring layers along the stacking sequence. The common structures are represented by their respective orderings of Ising spin along the stacking sequences which correspond to arrangements of the stacking layers.

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The model Hamiltonians for several common stacked crystals are well described by introducing the position vector and Ising spin in the previous paper. From the pairwise interaction model the model Hamiltonian for the hcp and the fcc structures is derived. Interactions of second neighboring atom pairs along the stacking sequence contribute mainly to construction of the hcp and the fcc structures. Physical meanings of the coupling constant J between Ising spins and that V between the position vectors are made clear. The behavior of the model Hamiltonian at low temperatures is analyzed on the basis of a systematic series expansion procedure. The structural phase transition from the fcc to the hcp structures with increasing temperature occurs in case where J is positive.

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We investigate the availability of Debye and Einstein approximations to calculate Debye-Waller factors in EXAFS, EELS and ARXPS for one-dimensional models. These approximate results were compared with the ab initio results shown in the previous paper II. For monatomic chains the Debye model can give a good result even for third and fourth cumulants. In the case of diatomic chains, a mixed model where Debye (Einstein) approximation is used for acoustic (optical) mode give quite a good result for harmonic second order cumulant. This simple approximation, however, gives rather poor results for third and fourth order cumulants and also anharmonic correction to the second order cumulant. This result is due to the fact the phases of the eigenvectors of the dynamical matrix play an important role for the accurate estimation of those thermal factors.

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We investigate a proton-phonon system which represents the hydrogen-bonded ferroelectric crystals, in particular KH₂PO₄(KDP). As a plausible model, `proton self-trapped state' model has been proposed. It is considered that, through the coupling to phonons, the proton on the hydrogen bond tends to be self-trapped at the shifted positions by breaking local symmetry of the surrounding atoms. The same coupling causes the quantum mechanical transition (phonon assisted tunneling) between the degenerated self-trapped states. At higher temperatures the transition is expected to become thermal activation type (incoherent tunneling). The results of neutron incoherent scattering study on KDP have been analyzed based on this model. The scattering function at T=150, K (T>T_c) shows satisfactory agreement with the observed spectrum by taking the relaxation time to cause incoherent tunneling to be 4× 10^-13, sec. The temperature dependence of the relaxation time is also investigated, which confirmed the validity of the thermal activation process with the activation energy of 37.1, meV.

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The first-order Raman spectrum of A₁ (648, cm^-1) mode in TeO₂ was measured at temperatures ranging from 77 to 473, K and the linewidths at these temperatures were obtained. The temperature dependence of the linewidths was analyzed by the phonon dispersion curves based on the shell model, and the result showed that it was caused approximately by the cubic anharmonic term in crystal potential energy.

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The structural phase transition from the hcp to the fcc structures with increasing temperature is studied theoretically by taking into account configurations of the position vector defined by the model Hamiltonian in the previous paper. The configurations are assumed to be in the short range order (SRO) approximation, that is, the orderings for the position vector near the structural phase transition or in the coexisting phase between the hcp and the fcc structures is much less than that in the perfect hcp and the perfect fcc structures but much more than that in non-crystalline states. First order structural phase transitions are derived theoretically, because SRO approximation induces an effective internal field proportional to Ising spin ordering. An effect of imperfection is considered by taking into account the Gaussian distribution of the coupling constant between Ising spins.

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Thermal contribution in the Gruneisen equation of state has been discussed to establish a universal description of the behavior of solids at high pressures and temperatures. It is shown that two new thermal variables introduced previously by the author, Θ and C, have the following properties: (1) they are conjugate with each other like temperature T and entropy S; and they form thermal internal energy by multiplication, (2) the variable C is the state variable depending only on entropy, while variable Θ defines a characteristic temperature; (3) success of the Debye model for the specific heat strongly suggests that functional relationships between C, S and specific heat C_v might be universal; (4) two results, (1) and (2), are found to be valid even when high-temperature anharmonic correction is included into the equation of state.

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An efficient and novel algorithm of calculating several thermal variables of solids at high pressures and temperatures has been proposed in this paper. They are obtained by once estimating a new thermal variable C, which is given only by the mechanical state variables, i.e., the pressure, density and internal energy. The variable C plays the role of the bridge between the mechanical and thermal state variables. Then temperature, entropy, and specific heat can be calculated by the help of the Debye model for the caloric equation of state for solids. By following this procedure, a very simple and efficient algorithm of calculating shock temperature has been developed, which contains no numerical integration. The method has been examined its feasibility by reproducing temperature values already tabulated elsewhere.

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The initial stage of the spinodal decomposition is examined focusing on the role of the density of triggers of the instability. Target patterns in two dimensions and onion-like structures in three dimensions are found when the number of triggers is small. We then explain a recent experimental observation for continuously photo-crosslinking polymer blend done by Tamai, Imagawa and Tran-Cong.

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Specific heat of (CH₃NH₃)₅Bi₂Cl₁₁ was measured by adiabatic calorimetry between 13, K and 325, K. A typical second-order type of anomaly was observed at 307.4, K. The enthalpy and entropy of transition were determined as 3.06, kJ, mol^-1 and 10.6, J, K^-1, mol^-1, respectively. A broad hump in the curve of specific heat was found around 160, K. Its contribution was estimated as the excess specific heat extending from about 100, K to 200, K over an assumed normal base line, which results in the values of enthalpy and entropy as 1.57, kJ, mol^-1 and 9.85, J, K^-1, mol^-1, respectively. The phase transition in the crystal was discussed in connection with such specific heat anomalies.

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The effect of isotope replacement of deuteron for proton on the ferroelectric ordering process in KH₂PO₄ has been discussed based on the `proton self-trapped state' model which has been recently proposed to describe the dynamical behavior of protons on the hydrogen bond. In this model, the tunneling two level scheme is precluded in the stable configuration of the lattice. Instead, the isotope effect is ascribed to the change in the adiabatic potential for phonons upon deuteration. The phase transition temperature T_c as well as the spontaneous polarization P_s have been explicitly given in terms of the coefficient of the lowest order expansion of the adiabatic potential with respect to the amplitudes of the phonon modes. The experimental isotope effects concerning T_c and P_s seem to evidence the validity of the present treatment.

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With a high-resolution two-crystal vacuum spectrometer equipped with beryl crystals, the Zn Lα emission spectra in fluorescence have been measured for Zn metal, ZnO, cubic ZnS, hexagonal ZnS, ZnF₂, ZnCl₂, ZnBr₂, ZnP₂ and Zn₃P₂. The emission spectra consist of a prominent peak Lα _{1, 2} and its high-energy structure, and are quite alike. The high-energy structure is primarily ascribed to the satellites as a result of multiple ionizations. The chemical shift is observed for the Lα _{1, 2} peak: The energy position of the Lα _{1, 2} peak is shifted toward lower energies with increasing the ionicity of the zinc compounds. The measured Zn Lα emission spectra are compared with available XPS, UPS and X-ray valence-band emission spectra and theoretical energy-band calculations on a common energy scale. It is shown that considerable p-d mixing occurs in the their valence band.

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The Fermi surface of the hexagonal compound LaGa₂ is studied using the de Haas-van Alphen (dHvA) effect. The observed results are compared with the LAPW band calculations published by Hariama and Yanase. The observed variations of the dHvA frequencies as a function of the magnetic field orientation are well explained by the calculated results. The factor for electron mass enhancement due to electron-phonon interaction is estimated to be 2 from the measured and calculated cyclotron masses.

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We investigate the effects of lattice vibrations on an electron gap in the Peierls-Frölich state using the Hartree-Fock approximation with respect to the electron-phonon coupling, considering both amplitude mode and phase mode with anisotropic dispersion. In the one-dimensional electron-phonon system, the electron gap is induced by the Umklapp scattering intermediated by the amplitude-mode phonon with momentum transfer of 2k_F. However, the phase-mode phonon gives the large fluctuation to the electron band and reduces the band gap. The band gap is determined by the competetion between the amplitude mode and the phase mode. We find that the band gap becomes narrower as the velocity of the phase-mode phonon u is increased. The band gap tail appears from the electron-phonon scattering. The electron scattering rate due to phonon is estimated to be π uΔ₀/2v_F, where Δ₀ is the electron band gap and v_F is the Fermi velocity.

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Electrical resistivity ρ and magnetic susceptibility of sintered Ca_1-xSr_xRuO₃ have been measured. The Weiss temperature changes sign at about x=0.5 in consistent with other studies. Temperature dependence of normalized ρ is almost identical for all the materials in the paramagnetic temperature range irrespective of the sign of magnetic interaction. The Rhodes-Wolfarth ratio is 1.3 for x=1. This ratio and the temperature dependence of ρ suggest that 4d-electrons in this system are in the intermediately localized state as in Ni. The sign of magnetic interaction is discussed in connection with the orthorhombic lattice distortion, and the antiferromagnetic interaction is attributed to this distortion.

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We have measured the specific heat in the temperature range between 1.5 and 50, K on UAl₂, classified as a paramagnetic 5f heavy fermion compound. A pronounced Schottky-like peak is observed at about 40, K with the peak height of 6, J/K mol in the electronic specific heat. Moreover, T³, ln, T temperature dependence in the specific heat is strongly suppressed below about 9, K in the case of U(Al_1-ySi_y)₂ (01-xPr_x)Al₂ (01-xPr_x)Al₂ and U(Al_1-ySi_y)₂ are varied with the lattice parameter. These behaviors are understood within the framework of the Kondo effect.

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The magnetic susceptibilities of liquid Ag-In alloy system were measured by using the Curie-Faraday method over a wide temperature range of 600 to 1100°C. The magnetic susceptibility curve at 1010°C was plotted against the alloy compositions. The magnetic susceptibility deviates from a linear change in the concentration of Ag rich side. The temperature coeffcient of the magnetic susceptibility shows a sharp minimum at 90 at% Ag and then increases to a maximum value at about 70 at% Ag. Using these results, the relationship between the medium rage order and the pseudogap in the density of state at Fermi level was discussed.

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The mode-mode coupling theory of spin fluctuations in the normal state of high-T_c cuprates is developed on the basis of the itinerant-localized duality picture of technically nested two-dimensional metals. This offers a unified description of the anomalies observed in the normal state of high-T_c cuprates. The so-called “spin-gap” behaviors of the resistivity, the specific heat, the uniform spin susceptibility, and the optical conductivity are characterized by the energy scale T^* of the crossover between the itinerant and the localized spin fluctuations, while those of the Hall coefficient, the thermo-electric power, the longitudinal NMR relaxation rate, and the neutron scattering intensity, are characterized by different energy scales less than T^*. The integrated weight of the nested spin fluctuation decreases when decreasing the temperature or approaching the perfect nesting, leading to the “spin-gap” behavior.

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Circularly polarised synchrotron radiation has been used to measure the spin-dependent magnetic Compton profile of the ferromagnet HoFe₂ at six temperatures from 10, K to 300, K. The magnetic Compton profiles have been analysed using appropriate free atom Compton profiles and a free electron Compton profile which has allowed the determination of the individual spin moments on the Ho and Fe sites and the diffuse moment; the last two are, to a first approximation, temperature independent. The Ho moment, which is antiferromagnetically coupled to them, reduces by a factor of two across the temperature range, leading to a spin compensation temperature of 210± 10, K. The experiments were performed with 45.9, keV photons at the KEK ARNE-1 station of the Accumulation Ring.

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⁶³Cu and ⁶⁵Cu NQR line shapes, spin-spin and spin-lattice relaxation rates in a high-T_c related Cu oxide, La₄BaCu₅O_13+δ , have been measured to clarify the difference between superconducting and non-superconducting Cu oxides from a microscopic view point. Although there are two crystallographically inequivalent Cu sites, only one pair of ⁶³Cu and ⁶⁵Cu NQR frequency spectra was observed. From the detailed study of the Fourier transformed spin-echo signal and that of the envelope decay, we attribute the above fact to an accidental coincidence of the NQR frequencies for these two sites. It is shown that the spin-lattice relaxation is manifested by the magnetic interactions in the measured temperature range of 1.4, K--420, K. The relaxation rate, 1/⁶³T₁, increases monotonically with increasing temperature, obeying 1/⁶³T₁=aT+bT³ above about 80, K, but shows a small swelling at low temperatures, suggesting a magnetic instability.

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The ³⁵Cl NQR spin-lattice relaxation times T_1Q in Ni(H₂O)₆SnCl₆ and Mg(H₂O)₆-SnCl₆ are determined mainly by the fluctuations of the electronic magnetic fields caused by electron-spin flips and of the electric field gradients due to lattice vibrations, respectively. In addition, we have observed a double minimum and a dip in T_1Q for the Ni and Mg compound, respectively. This arises from the fluctuation of the electric field gradients at the chlorine nuclei caused by reorientational motions of the nearby cations that result in slight dynamic disorders of the proton sites. This type of relaxation mechanism has not been observed extensively so far, because the disorder in question is limited only to such one as can affect the NQR relaxation but at the same time does not prevent us from observing the NQR signals. The nature of the relaxation mechanism is discussed.

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We have investigated reflection spectra at 4, K for single crystals of (CH₃NH₃)₄PbI₆· 2H₂O which consists of isolated [PbI₆]^4- octahedra, (C₁₀H₂₁NH₃)₂PbI₄ and (CH₃NH₃)PbI₃, which consist 2- and 3-dimensional networks of [PbI₆]^4-, respectively. The formation energy of the lowest exciton state increases from 1.633, eV to 3.4, eV with decreasing the dimensionality in the crystal structure, from the transfer energy between the adjacent octahedra is estimated to be about 0.5, eV. The on-site Coulomb energy in the octahedron is estimated to be 2.3, eV. We suggest that the large on-site Coulomb energy enhances the exciton binding energy, especially in the 2-dimensional system.

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The Stark broadening by inhomogeneous electric fields in highly compensated p-type InSb has been studied through far-infrared absorption measurements. In particular, we have paid attention to the time-resolved absorption spectrum for acceptors under pulsed photoexcitation. It is found that the full width at half maximum (FWHM) for the absorption line increases as the lapse of time after photopulse excitation increases. In explanation of the broadening mechanism due to the Stark effect by electric field arising from inhomogeneous distribution of the ionized impurities around neutral acceptors, we have employed the approach based on the Monte Carlo simulation. The inhomogeneity of the field-distribution becomes larger with increasing the ionized impurities. This theoretical calculation gives fairly good agreement with the observed broadening of the FWHM in spectrum.

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Transmission spectra of NaCl in both microcrystalline and bulk states under pressure have been measured at room temperature in a far-infrared region. Experiment under pressure up to 3.2, GPa was done using a diamond anvil cell in operation with the synchrotron radiation as a light source in the far-infrared region. The surface phonon at a atmospheric pressure (P=0) was found to locate at 198, cm^-1 for the spherical shape of microcrystal and 184.8, cm^-1 for the cube-like shaped microcrystal, as expected by a conventional continuum model which holds for the surface phonon at P=0. The absorption bands of the surface phonons as well as the TO phonon mode were found to show a blue shift with pressure but the shifts with pressure were found to be different each others according to the shapes of the microcrystals. The difference of the energy shifts between a spherical and a cube-like shaped microcrystal under pressure was interpreted by the scheme of the extended continuum model.

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The difference of spin label density between the phases with different fluidities was studied in multilamellar DPPC liposomes. ESR spectra of stearic acid spin labels of unprotonated form were observed. The spectral intensity due to the labels in lipid was measured on comparing to that due to the labels in the buffer solution. The intensity ratio of these two lines was calculated in both the gel and liquid crystalline phases. The label density of 16-SAL in the liquid crystalline phase is 2.8 times more concentrated than that in the gel phase. The values are 1.85 for 5-SAL and 5.6 for 12-SAL. The application of these values to the case when two regions with different fluidities coexist in a lipid bilayer was studied.

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