Materials Literature
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We present a first-principles theory for the quasiparticle energies of semiconductors and insulators. The full dielectric matrix is used to evaluate the nonlocal, energy-dependent electron self-energy operator. Both local-field effects and dynamical screening are found to be essential for understanding quasiparticle e…
ABSTRACT A correlation which is a function of the reservoir temperature and the heptanes plus mole fraction has been developed to predict the maximum condensation during pressure depletion of retrograde condensate fluid reservoirs. A generalized equation of state has been used in phase behavior calculations. The phase…
ABSTRACT The chemical instability of Polyacrylamide polymer during both polymer and micellar-polymer flooding can seriously affect flood performance. Results of this study utilizing special laboratory techniques and long-term tests to simulate conditions typical of petroleum reservoirs show the effects of key variable…
Precise measurements of the X-ray attenuation coefficient of crystalline silicon have been made in the energy range 25 to 50 keV. The results are compared with theoretical predictions and earlier measurements. A systematic discrepancy between theory and experiment is observed. The most likely cause of the disagreement…
The electron-vibronic band with its no-phonon (NP) transition at 0.9351 eV which was recently detected in heat-treated silicon is strong after irradiation of silicon and has been studied in high-resolution photoluminescence. The defect exhibits a quasi-local mode of quantum energy h(cross) omega =66.3 meV which is obs…
Magnetocaloric experiments are performed in an attempt to decide whether S-shaped magnetization versus field curves M(B) of MnAs1−xPx-crystals (x = 0.08, x = 0.09) are due to magnetization processes or reflect a transition between two different magnetic states. Extra heats of formation which are observed under adiabat…
Electrical conductivity, σ, and thermoelectric power (Seebeck coefficient), S, of glassy As40Se60−xTex (x = 10, 20, 30, and 40) are investigated. The difference between activation energies for σ and S does not monotonically change with Te content. The experimental data are interpreted by a parallel conduction model, w…
Recent EPR studies of the 4d1 configuration ion Zr3+ in the tetragonal-symmetry orthophosphate hosts LuPO4, YPO4, and ScPO4, have led to additional investigations of d1 configuration ions associated with unusual valence states of other elements. Single crystals of LuPO4, YPO4, and ScPO4 doped with hafnium were grown a…
A theoretical analysis of the experiments of Holland and Hall [Phys. Rev. B 27, 7765 (1983)] is given. The metal-island film is characterized by an effective anisotropic dielectric function. Formulas for reflection and transmission coefficients for an anisotropic layered structure are given. Calculated normal and non-…
We have studied the oscillator strength of the lowest 1s heavy excitons in GaAs-AlAs quantum wells as a function of well-layer thickness by means of optical absorption. The oscillator strength of the lowest 1s heavy excitons is largely enhanced with the decrease of well-layer thickness. The result is the first full ex…
The dielectric constants along the c ' axis of Cs 3 H(SeO 4 ) 2 and its deuterated crystal were measured in a temperature range from 5 K to 460 K. It was found that Cs 3 H(SeO 4 ) 2 undergoes three phase transitions at 451 K, 364 K and 50 K. The dielectric constant of Cs 3 H(SeO 4 ) 2 shows a small peak at 50 K, and i…
A 3-D Penrose transformation is found. The expansion rates, τ 3 in linear dimension and τ 9 in volume, are by far the larger than τ and τ 3 respectively ever believed. The transformation decides only the skeleton uniquely, leaving some other degrees of freedom undecided. It strikingly differs from the deterministic 2-…
The effect of pressure on the thermal hysteresis of the high-spin (5T2) ∏ low-spin (1A1) transition in [Fe(phy)2](BF4)2 and [Fe(phy)2](ClO4)2 has been studied (phy=1, 10-phenanthroline-2-carbaldehyde phenylhydrazone). An increase of the hysteresis width ΔTc as well as of the residual fractions nres5T2 and (1−n5T2)res…
The powder Raman spectra and the polarized infrared absorption spectra of a polycrystalline oriented film of (1:1) CT complex of 5,10-dihydro-5,10-dimethylphenazine (M2P) with 7,7,8,8-tetracyanoquinodimethane (TCNQ) are reported together with the polarized reflectance infrared spectra of a mosaic of single crystals [(…
The spectra of methane adsorbed at low temperature in NaA zeolite show two strong effects of the field existing in the cavities: (i) the appearance of the ν1 forbidden band which increases when decreasing the temperature and (ii) the splitting of the ν3 degenerate band. The variation with T of its components lead to t…
The two-fluid theory of phonon transport and thermal conductivity recently proposed by the author is refined, with the major source of error identified as the previous neglect of the subset of normal processes called NN processes. A correction is provided for these processes, which are mainly those of phonon splitting…
A microscopic model of the effective deactivation of the ZnS visible photoluminescence by iron impurities is presented. It is shown that strong photoionization (${\mathrm{Fe}}^{2+}$\ensuremath{\rightarrow}${\mathrm{Fe}}^{3+}$) absorption enables an effective transfer of energy between centers active in luminescence pr…
Overall rate constants for the removal of N2(A,v) by O2 and O were measured at 298 K in a rapidly pumped flow reactor using laser-induced fluorescence (LIF) detection of N2(A,v) by excitation in the first positive system of N2, B(3πg)←A(3Σ+u). O atoms were generated in microwave discharges of pure O2 prepared by therm…
Conformational and displacive molecular defects in even-numbered paraffins ${\mathrm{C}}_{\mathrm{n}}$${\mathrm{H}}_{2\mathrm{n}+2}$, with 22\ensuremath{\le}n\ensuremath{\le}28, are studied as a function of temperature by means of small-angle x-ray diffraction. The amplitude of the molecular longitudinal motion in the…
The process of growing large diameter single crystals of Al2O3:Ti3+ by vertical solidification of the melt is described, and some of the problems in producing high-optical quality material are discussed. The characterization of the distribution and valance state of titanium ions was performed by x-ray techniques and l…