Showing papers in "Journal of Physics and Chemistry of Solids in 1981"

TL;DR: In this paper, a thermodynamic model based on the regular solution approximation is presented and a formalism, suitable for phases with an arbitrary number of sublattices, is developed, in order to simplify the analytical expressions for the integral Gibbs energy.

TL;DR: In this paper, the authors employed IR and Raman spectroseopy to study well characterized samples of the following poly(ethylene oxide) (PEO) complexes: PEO·NaBr, PEO•NaI, PIO·NaSCN, POO·NaBF4, PO•NaCF3SO3, POE·KSCN and PEO-RbSCN.

TL;DR: The phase transitions in the ZrO2-YzO3 system have been investigated as a function of temperature using Raman scattering and the cubic phase was found to be structurally disordered and the spectrum has been compared with a one phonon density of states derived from a rigid ion model.

TL;DR: In this article, the unit-cell parameters and crystal structures of five rutile-type compounds, including TiO 2, SnO 2 and MnF 2, were determined at pressures to 50 kbar at 20°C.

TL;DR: In this article, the authors used thermogravimetrie and electrical measurements to give accurate informations on the nature of the defects produced by reduction of TiO2 between 800 and 1100°C.

TL;DR: In this article, the electron mobility in Cdin x,Hgin1− x Te/0 x /0.33, 10 15 cm −3 n 10 18 cm−3, 4.2 K ⩽ T ⌽300 K/ and of the thermoelectric power of intrinsic HgTe from 300 K down to 5 K were analyzed in terms of the variational solution of the Boltzmann equation.

TL;DR: In this article, a modified Born stability criterion that 1 2 (C 11 − C 12 ) B equals about 0.2 is reached at the phase transition pressure P t, and the ratio β t α t of the second-order bond-bending β t to bond-stretching α t, force constants is about 1.1.

TL;DR: In the case of R Fe 6 Al 6 (R = Y, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb), the magnetization curves start with low values at low temperatures and rise to very high values at T max ~ 230 K and then drop to 0 at T c ~ 330 K as discussed by the authors.

TL;DR: The black cubic compound CsSnBr3 as discussed by the authors has a band gap of 0.34 eV up to 303 K when a minor phase transition occurs and a second emisssion band occurs in the near IR.

TL;DR: In this paper, a simple model is given which permits the determination of the composition at which mixed alkali halides reach their maximum conductivity and diffusivity, which requires only the elastic data of the one component and the molar volumes of the two end members.

TL;DR: In this article, the Raman spectra of the orthorhombic (II) and high pressure (III) phases of titanium dioxide at pressures to 372 kbar and effects of temperature and hydrostatic pressure on Raman spectrum of the tetagonal cassiterite-like phases of TiO 2, GeO 2 and SnO 2 are described.

TL;DR: In this article, Li2MCl4 with M = Mg, Mn, Fe and Cd showed very high lithium ionic conductivity in the solid state, which was established with the help of emf measurements.

TL;DR: In this article, Clausius-Clapeyron equation was used to calculate the enthalpy and entropy changes of cyclohexane, cyclopentanol, and cyclochenane up to 3000 bars.

TL;DR: In this article, a simple method has been proposed to calculate the partial molar entropy for interstitial solid solution with exclusion of nearest neighbor sites, and its accuracy has been tested by comparing its results with exact results known for hard sphere lattice gases.

TL;DR: Oxygen-18 has been used as a tracer to study diffusion in the c-direction of rutile single crystals in the temperature range 1173-1473K as mentioned in this paper.

TL;DR: In this paper, the dielectric relaxation experiments at ambient pressure by Fontanella et al. were analyzed and gave migration entropies that agreed with values calculated from a macroscopic model developed in the past by the authors.

TL;DR: In this paper, the generalised Born repulsive potentials for NaCl-type alkali halides have been re-evaluated using more reliable, recently published thermodynamic data and van der Waals energy coefficients.

TL;DR: In this paper, the authors analyzed the heat capacity data for solid nickel with the aid of auxiliary measurements of expansion coefficient, compressibility, vibrational and electronic densities of states, elastic constants and magnetic exchange integral and susceptibility obtained from the literature.

TL;DR: The crystal structures and electrical properties of CaAs3, BaAs3 and EuAs3 have been studied by single crystal X-ray investigations, temperature dependent resistivity measurements and optical measurements as mentioned in this paper.

TL;DR: X-ray diffraction measurements show that on heating Mg 2 NiH 4 in a 1 atm pressure H 2 atmosphere, above ∼250°C it transforms into a cubic structure, metal atoms in CaF 2 arrangement, a = 6.525 A, b = 6594 A, c = 6490 A and β = 93.1°.

TL;DR: In this article, the UV-PE spectra of polycrystalline metal sesquioxides have been studied and shown to be consistent with localised 3D electrons.

TL;DR: In this paper, the diffusion constant of the lowest triplet self-trapped exciton in NaCl with Li+ ions was investigated and the decay of the π luminescence induced by an electron pulse and the time change of the luminecence from (Vke)Li were explained in terms of the characteristic equation of the diffusion-limited reaction of the low triplet excitons with the Li+ ion.

TL;DR: The concentration and temperature dependence of the self diffusion coefficient, D, of H in Group V transition metals Nb and Ta has been measured for the α' phase in this article, where a pulsed field gradient, NMR spin echo technique was utilized to measure D. In both systems, the activation energy increases with hydrogen concentration while the preexponential factor is not strongly concentration dependent.

TL;DR: In this article, the authors measured the solubility limit and diffusion coefficient of I 2 in (CH) x polymer with a radiotracer technique and showed that the concentration of iodine in the polymer is a function of the surrounding concentration outside the film at equilibrium.

TL;DR: In this paper, the cathodoluminescence of single crystals of Cu In S 2 obtained by iodine chemical transport was studied as grown crystals and crystals annealed in In, S, (In + S), or in vacuum.

TL;DR: In this paper, single crystals of NaCl containing volume fractions of up to 28% of the Suzuki phase Cd□Na6Cl8 have been subjected to a range of frequencies (10-107 Hz).

TL;DR: In this paper, a cell model for tenary solid solutions containing a substitutional and an interstitial solute species is considered and the effects of the dilation of the solvent lattice by the substitutional solute are taken into account in an appropriate manner using the currently limited elastic data available.

TL;DR: For trigonal, vitreous and red amorphous Se the phonon densities of states F ( h ω) have been determined by inelastic neutron scattering from powder samples as mentioned in this paper.

TL;DR: In this paper, the electrical conductivity of cuprous oxide in the range of temperature 650-1100°C and for oxygen partial pressures greater than 10−6 atm was investigated.

TL;DR: In this paper, the diffuse transition of a rare earth ion doped SBN (Ba x Sr 1− x Nb 2 O 6 ) was studied by measuring the spontaneous polarization P s, and the dielectric constant ϵ.