Materials Literature
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Some rate data for the transfer of a deuterium atom tracer between hydrogen and water vapor, catalyzed by platinum supported on γ-alumina, are reported. Above 100 °C the transfer rate measured at 1 atm total pressure is shown to be free of mass transfer effects, and obeys an initial first order dependence on water vap…
Reflectivity and wavelength-modulation-derivative-reflectivity spectroscopy have been performed on the alloy series ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Te}$ throughout the compositional range $0\ensuremath{\le}x\ensuremath{\le}1$. PbTe and SnTe reflectivities were studied from 0.5 to 21 eV and th…
The pressure dependence of the ionic conductivity of KCl, NaCl, KBr, and NaBr has been measured to 6 kbar in the intrinsic and extrinsic temperature regions. In the intrinsic region the conductivity deviates markedly from a simple exponential decrease with pressure. A detailed analysis, including contributions from an…
The Auger spectra of vanadium metal and of the oxides VO0.92, V2O3, and VO2 have been studied. Chemical shifts on the order of 0.6 eV per oxidation number have been observed for the vanadium inner shell Auger transitions. Relative intensities of the oxygen and vanadium Auger peaks could be used to determine the surfac…
The infrared and Raman spectra of acetone oxime have been investigated from 70 to 4000 cm−1. Spectra have been obtained for the gaseous, liquid, and polycrystalline materials, and the data have been interpreted in detail. A suggested vibrational assignment for the molecule is based upon group frequency correlations, r…
The polarization properties of the various diffracted orders from a grating are determined ellipsometrically. The ratio ${\ensuremath{\rho}}_{m}$ of the far-field complex reflection coefficients for the $p$ and $s$ polarizations for any order $m$ is measured. This information is complementary to the data available fro…
The dc electrical resistivity $\ensuremath{\rho}$ and Hall effect were measured in $n$-type EuS single crystals. Data were taken from 300 to 2 K in magnetic fields $H$ up to 140 kOe. At room temperature all samples had resistivities of the order ${10}^{\ensuremath{-}2}$ \ensuremath{\Omega}cm and contained $n\ensuremat…
By changing the location of Fermi level of TiO 2 by lithium doping, ESR signals of some transition metal impurities in this crystal were pursued. The conclusions are: the Cr 3+ , Mn 4+ and Fe 3+ levels are near or overlapped with the valence band, the V 3+ , Mn 2+ and Fe 2+ levels are near the conduction band, the Cr…
CsCl type NH 4 Br crystal has been treated as an Ising spin-phonon coupled system to explain the phase transitions associated with the orientational order of NH 4 + ions. The appearance of two ordered phases is explained as essentially due to the fact that the direct interaction between NH 4 + ions stabilizes parallel…
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Nonresonant phonon-assisted energy transfer between trivalent rare earth ions is studied using Y 2 O 3 as the host crystal. The transfer probabilities are obtained from the analysis of the decay rates of donor luminescence for various combinations of donor and acceptor ions in which energy gap, i.e. mismatch of energy…
The valence bands of I-III-${\mathrm{VI}}_{2}$ compounds result from a hybridization of the noble-metal $d$ levels with $p$ levels on the other atoms. This results in large downshifts in the energy gaps relative to the binary analogs, and the absence of spin-orbit splitting in the uppermost valance bands of several su…
The frequencies of certain normal modes of vibration of the graphite lattice have been studied on samples of high-quality pyrolytic graphite by coherent, inelastic-neutron-scattering techniques. Some of the data are not compatible with certain restrictions imposed by the valence-bond model as presented by Young and Ko…
High-resolution gold-valence-band photoemission spectra were obtained by the use of monochromatized $\mathrm{Al} K\ensuremath{\alpha}$ radiation and a single-crystal specimen. After background and scattering corrections were made, the results were compared directly with broadened theoretical density-of-states function…
Abstract Natural diamonds have been heated in the temperature range of 1850 to 2000 °C at zero pressure and the rates at which diamond transforms to graphite measured. For {111} and {110} surfaces activation energies of 253+18 and 174+12 kcal mol-1 (1159 + 75 and 728 + 50 kJ/mol) respectively have been obtained. Diamo…
Crystallographic studies of La 2 O 3 and the oxides isostructural with it have failed to decide between noncentrosymmetric space group D 3 2 (P321) and the centrosymmetric space group D 3d 3 (P3m1) for their structure. The infrared and Raman spectra of La 2 O 3 and Nd 2 O 3 have been obtained and the absence of coinci…
The far infrared spectra of the rare earth sesquioxides, cerium dioxide, and nonstoichiometric praseodymium and terbium oxides have been observed over the range 10-250 cm -1 at liquid helium temperatures. Absorption due to the excitation of phonons and low-lying electronic states of the rare earth ions occur in this r…
The temperature dependence of the flow alignment angle has been measured in two nematic liquid crystals, ${p}^{\ensuremath{'}}$-methoxybenzylidene-$p\ensuremath{-}n$-butylaniline and $p\ensuremath{-}n$-hexyloxybenzylidene-${p}^{\ensuremath{'}}$-aminobenzonitrile. For both compounds this angle reaches a peak value at t…
We studied the second derivative of the magnetization with respect to the magnetic field, $\frac{{d}^{2}M}{d{H}^{2}}$, for polycrystalline materials having uniaxial anisotropy. Evidence is given of a singular point located at $H={H}_{A}$, the anisotropy field. The observed sharp peak is associated with the infinity at…
The crystal structure of pyridinium hexaiodopentaargentate, (C(5)H(5)NH) Ag(5)l(6), is unique among those of the halide and chalcogenide solid electrolytes in that face-sharing iodide octahedra as well as face-sharing tetrahedra and face-sharing between octahedra and tetrahedra provide the paths for silver ion transpo…