Materials Literature
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By a molecular-dynamics simulation of a three-dimensional system of 4000 particles, we show that the long-time tail of the velocity autocorrelation function has the form ${\ensuremath{\alpha}}_{0}{t}^{\ensuremath{-}\frac{3}{2}}$, where $t$ is the time and ${\ensuremath{\alpha}}_{0}$ a coefficient depending on the kine…
Abstract The energies of the LMM Auger transitions show, for certain elements, a far greater dependence on chemical state than do the binding energies of the individual electrons involved in the transitions. This behaviour is not predicted by the existing models for the energy of an Auger transition but is of consider…
Normalized differential and integral electron-impact cross sections for elastic scattering and for the excitation of the $^{2}D_{\frac{5}{2}}$, $^{2}D_{\frac{3}{2}}$, and $^{2}P_{\frac{3}{2},\frac{1}{2}}$ levels of atomic copper have been determined at 20 and 60 eV. An unexpectedly large cross section was found for th…
Measurements are reported of the effect of field and temperature on decaying and steady currents in an epoxy polymer. Fields up to 140 MV m −1 were used and the steady current was found to increase as exp (α F ½ ). The decaying currents followed the t − n law and increased much less rapidly with increasing field and t…
Acoustic transients can be thermally generated in water by pulsed microwave energy. The peak pressure level of these transients, measured within the audible frequency band as a function of the microwave pulse parameters, is adequate to explain the "clicks" heard by people exposed to microwave radiation.
On evaporated layers of amorphous As2Se3 the photoconductivity is studied as a function of temperature and illumination intensity. An extremely slow decay of the photocurrent is found which is almost independent of temperature in the range of high excitation. At low excitation level the recombination is considerably e…
Infrared spectra of sulfur monochloride in various solid matrices were taken at 12°K. The sharpness of the band seen at 550 cm−1 compelled its assignment as the S–S stretching mode. Enrichment of samples with 37Cl led to the identification of the chlorine isotopic splittings on the two S–Cl stretching modes observed n…
Damping and modulus measurements were made on high-purity copper subjected to both quenching and 1.0-MeV electron irradiation. During isothermal annealing at room temperature, following quenching from 700\ifmmode^\circ\else\textdegree\fi{}C, we observe a monotonic decrease in the logarithmic decrement with a concurren…
The electronic structures of oxygen adsorbed on silicon (111)2\ifmmode\times\else\texttimes\fi{}1 cleaved, (111)7\ifmmode\times\else\texttimes\fi{}7, and (100)2\ifmmode\times\else\texttimes\fi{}1 surfaces and of oxidized silicon have been investigated by combining electron energy-loss spectroscopy (ELS) and ultraviole…
Measurements of changes in the elastic constants of copper and their temperature dependences resulting from stage-${I}_{C}$ close pairs and stage-${I}_{D}$ isolated interstitials are used to investigate defect configurations. The relative elastic-constant changes below 4 K per unit concentration $\ensuremath{\gamma}$…
Oxygen self-diffusion coefficients in single crystal spinels were determined for three compositions of MgO · Al2O3, MgO · 1.2Al2O3, and MgO · 2.2Al2O3 by a gas-solid exchange technique utilizing 18O as a tracer. The temperature dependence of the self-diffusion coefficient for MgO · Al2O3 was expressed as D = 0.89 exp(…
Thermoreflection and thermotransmission measurements were made on thin semitransparent films of Ag at about 320, 120, and 15 K in the range 3.40-4.40 eV. The results are in fairly good agreement with the theory presented in the preceding paper but show that thin metal films evaporated on amorphous substrates become st…
The X-band ESR spectra of 63Cu2+ doped zinc Tutton's salt enriched to 16 at.% in 17O isotope was studied in a single crystal at 20, 77, and 290°K. The powder spectrum of the same material was studied over the temperature range 10–350°K at X band and 120–290°K at Q band. The observed values of the g tensor and 63Cu and…
The absorptivity or reflectivity of crystals of V, Ta, and Mo was measured from 0.1 to 35 eV. The data were Kramers-Kronig analyzed to determine the dielectric functions. The inadequacy of a simple Drude model to describe absorption at low energy is discussed. Structure in the dielectric functions is discussed in term…
The temperature dependence of the band parameters associated with the electron pockets in bismuth is presented from 4 to 280 K, based on analysis of magnetoreflection data. This first determination of the bismuth band parameters over a wide temperature range shows that the same form of the energy dispersion relation i…
Refinement of the crystal structure of V${\mathrm{O}}_{2}$ at 360 and 470 K in the metallic rutile phase shows that both the vanadium and oxygen thermal displacements are larger than those found in rutile phases of Ti${\mathrm{O}}_{2}$ and Cr${\mathrm{O}}_{2}$ or monoclinic phases of V${\mathrm{O}}_{2}$ or ${\mathrm{V…
The electronic structure of an isolated TCNQ mulecule has been calculated by the self-consistent statistical-exchange multiple-scattering method. By using overlapping atomic spheres in place of nonoverlapping atomic spheres, a significant increase in physical realism has been achieved. The theoretical model provides a…
An experimental study of the occurrence of temperature oscillations in molten gallium contained in a rectangular boat and heated from the side is reported. The dependence of the critical temperature difference across the boat for which oscillations set in upon the boat dimensions and upon the strength of a transverse…
The validity of a four-parameter semi-quantum (FPSQ) model to fit infrared reflectivity spectra of crystals having a large number of phonon branches is discussed in view of the results of anharmonic quantum theories. The form of the quantum damping function may indeed be simplified when the two-phonon density of state…
Suspension and bulk-polymerized commercial polystyrenes have been fractured by cleavage and the resulting surfaces examined by optical and scanning electron microscopy. The method of styrene polymerization was found to influence the initiation and propagation of fracture, probably owing to the differing amounts of ins…