Materials Literature
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A simple phenomenological model of the electronic structure of the pseudogap of an amorphous semiconductor is considered, and used as the starting point for a systematic investigation of the processes that determine the nature of the photoluminescence. Many of the most striking features of these materials are shown to…
The relationship between dipole-field sums and Lorentz tensor components in single crystals is described and used to develop a method for computing the tensor components via rapidly convergent sums of Bessel functions. The method is used to compute Lorentz factors for simple, body-centered, and base-centered orthorhom…
The phonon dispersion curves for graphite intercalation compounds (GIC's) are calculated for the case of potassium, rubidium, and cesium intercalates. The model is based on the staging periodicity in these compounds in that it assumes that the symmetry of the graphite crystal is preserved upon intercalation. The effec…
The crystallographic parameters of compounds MnAs 1- x P x (0≦ x ≦0.275) are determined as a function of temperature between about 100 and 600 K. It is found that these crystals except for MnAs take a MnP type structure in low temperature side and transform to a NiAs type at critical temperatures. These structural tra…
Elastic scattering by a small inhomogeneous sphere, comprised of two concentric spherical regions, may be abnormally low if the dielectric constant of the external medium is intermediate between those of the two regions. When one of these regions is a metal with a real negative dielectric constant, there may also be v…
The (111) and (110) surfaces of Pt, clean, oxidized, and covered by CO, have been investigated for surface $4f$ core-level binding-energy shifts. For the (111) face the surface $\mathrm{Pt}4{f}_{\frac{7}{2}}$ core level was shifted by 0.40\ifmmode\pm\else\textpm\fi{}0.05 eV to lower binding energy relative to the bulk…
We report on careful line shape studies of slow motional and orientation dependent ESR spectra of a deuterated liquid-crystal-like spin probe dissolved in a benzilidene-derivative (40,6) and in cyanobiphenyl derivative (S2 and 5CB) liquid crystals. The simulation of the ESR spectra is based on the Lanczos algorithm re…
The experimental data of the ${\mathrm{Zn}}_{3}$${\mathrm{P}}_{2}$ absorption edge are analyzed for single crystals and thin films. The isotropic Kane band-structure model, with the introduction of a valence-level splitoff due to crystal-field interaction is used to calculate the absorption coefficient. The best fit t…
The lattice dynamics of pristine graphite is presented with the use of a Born---von K\'arm\'an model. With the consideration of interactions to fourth neighbor both intraplane and interplane, good agreement is simultaneously obtained with ir, Raman, and inelastic neutron scattering measurements of lattice modes and wi…
The heating rate is an important, though often neglected experimental variable in TL measurements. Lithium fluoride (TLD-100) samples have been heated at rates up to 100 degrees C s -1 during TL readout. The change in TL glow peak intensities and (Mg 2+ -V - ) dipole concentration during readout have been investigated…
The first numerical determination of the thermodynamic isotropic-nematic transition in a simple three-dimensional model fluid, viz., a system of infinitely thin hard platelets, is reported. Thermodynamic properties were studied with use of the constant-pressure Monte Carlo method; Widom's particle-insertion method was…
Polarized axial and orthoaxial luminescence spectra in the 7 Fj (J=1, 2, 3 and 4)←5 D 0 transition regions of Eu3+ in single crystals of trigonal Na3[Eu-(oxydiacetate)3]. 2NaClO4.6H2O are reported and analysed. Differential circular polarization (left-handed versus right-handed) is measured in the axial luminescence s…
The Lebwohl-Lasher model of a nematogen provides a simple system with which to study the order-disorder transition and to examine the properties of the nematic phase. We have investigated the model containing 203 particles over a small temperature range characteristic of that for real nematogens using the Monte Carlo…
This paper reports x-ray intensity analysis of the superlattice reflections associated with the order-disorder transition of di (tetramethyltetraselenafulvalenium) perrhenate [${(\mathrm{TMTSF})}_{2}$Re${\mathrm{O}}_{4}$] at ${T}_{c}\ensuremath{\simeq}180$ K. The results confirm the earlier proposed anion ordering and…
Based on the theory developed by the present authors in preceding papers, the values of the librational frequencies at the Brillouin zone center and the thermodynamic characteristics of solid N2, CO, N2O, and CO2 in the orientationally ordered phase are determined. The results obtained are compared with experimental d…
Machine learning (ML) is transforming all areas of science. The complex and time-consuming calculations in molecular simulations are particularly suitable for an ML revolution and have already been profoundly affected by the application of existing ML ...Read More
It has been shown that isotopically labelled sheep wool wax is carried passively along the wool fibre as a band by growth of the wool, and that it does not flow along the fibre to any large extent during experiments of several months. This supports the view that the function of sebum, in mammals in general, is to prot…
We consider the steady state reaction-diffusion problem for a permeable catalytic particle with Langmuir–Hinshelwood kinetics under isothermal and quasi-isothermal conditions. It is known that there may be multiple solutions due to either strong adsorption or external thermal effects; in the first case, an arbitrarily…
To a first approximation the addition of a solute (Ti) to a solvent (Fe) results in a change of lattice parameter which varies linearly with the atomic concentration of solute. However, it has been proposed by Raynor that in a transition-metal alloy system this ideal behaviour is not necessarily obeyed. A survey of pu…
AThe present paper deals with the findings of an experimental comparison of the optical properties of cholesteric (chiral nematic) and chiral nematic) and chiral semctic phases.