Materials Literature
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We have calculated, by means of ab initio techniques, the equilibrium geometries, total energies, binding energies, and fragmentation energies for the clusters ${\mathrm{B}}_{\mathit{n}}$, with n=2--8, in both the neutral and cationic states. The ionization potentials for the neutral clusters have also been calculated…
The one- and two-electron ground-state energies of a silicon sphere embedded in an amorphous silicon dioxide matrix are calculated as a function of the sphere size. The electron-electron interaction and polarization effects are treated by perturbation; our quantum-mechanical calculation is valid for small spheres with…
Abstract The relation between atomic structure and elastic properties of grain boundaries is investigated theoretically from both atomistic and continuum points of view. A heterogeneous continuum model of the boundary is introduced where distinct phases are associated with individual atoms and possess their atomic lev…
We describe a phenomenological model for the thermal fluctuations of a three-phase contact line in the case of three fluid phases. The model is an extension of an earlier model for the case of two fluids and one solid. In the previous model only one interface was allowed to fluctuate, and the contact line was constrai…
Ci0H6FI2NiO6, M,=508.9, monoclinic, C2/c, a = 21.195 (5), b = 8.247 (2), c = 9.741 (2) ,/3 = 95.91 (2) °, V = 1693.6 (7) )~3, Dx = 1.996 Mg m-3, Z=4, #=1.298mm-1, A(MoKa)=0.71073./~, F(000)=1000, T=298K, R=0.0369 and wR = 0.0645 for 157 variable parameters (S= 0.59) and 1112 reflections with F>0~r(F). The Ni atom pos…
We describe a phenomenological model for the thermal fluctuations of the line of contact between two fluid phases and one solid phase. The line of contact between the three phases is constrained to lie along the solid surface, which is assumed to be smooth, flat, and horizontal with respect to gravity. In order to mod…
In order to test the proposal that the anomalous valence-level photemission spectrum of Am results from a divalent (5${\mathit{f}}^{7}$) surface layer, we have performed variable-takeoff-angle experiments on the metal. 4f spectra obtained at 10\ifmmode^\circ\else\textdegree\fi{} and 85\ifmmode^\circ\else\textdegree\fi…
Synchrotron radiation soft x-ray photoemission spectroscopy was used to characterize the surface chemistry of p-InP before and after exposure to H2S gas at ambient temperature. The effect of the H2S dosing was determined by in situ photoemission measurements which were acquired after each gas exposure in order to obse…
Quasielastic light-scattering measurements are reported for a chiral smectic-C material as a function of enantiomer concentration and applied electric field. The elastic constant ${\mathit{B}}_{1}$ and associated viscosity have been determined. More importantly, it was found that ${\mathit{B}}_{1}$ is composed of a ba…
The dielectric properties and positron annihilation lifetime spectra of the ceramics with the nominal composition Sr1−xLaxTiO3 (0≤x≤0.06) were measured. The dielectric properties and relaxation behaviors, which varied obviously with lanthanum content, were explained by a charge compensation model. The defect structure…
Absorption, excitation and emission spectra and lifetime measurements in cerium-doped lanthanum fluoride single crystals were obtained using both one- and two-photon spectroscopy techniques. It is shown that two kinds of fluorescent centres are present. In weakly doped systems, a rapid fluorescence around 300 nm domin…
The critical behavior of sliding charge-density waves just above threshold is analyzed. In 4-\ensuremath{\epsilon} dimensions, the exponent \ensuremath{\zeta}, defined through ${\mathit{I}}_{\mathrm{CDW}}$\ensuremath{\sim}(V-${\mathit{V}}_{\mathit{T}}$${)}^{\mathrm{\ensuremath{\zeta}}}$, is found to be 1-\ensuremath{\…
Strain compensation is an important aspect of heterostructure engineering. In this letter, we discuss the synthesis of pseudomorphic Si1−yCy and Si1−x−yGexCy alloy layers on a silicon (100) substrate by molecular beam epitaxy using solid sources and the controlled strain compensation that results from the introduction…
The common observation of cellular substructure ((1 ÷ 10 -2 )mm) at the sea-ice-ocean interface is explained by modelling the natural solidification of seawater as that of a dilute H 2 O-NaCl solution. Linear and nonlinear perturbation theories reveal that the one-dimensional planar steady state is morphologically uns…
Raman-scattering experiments have been carried out on stage-2 silver-intercalated ${\mathrm{TiS}}_{2}$ single crystals. Below a transition temperature near 300 K, the intercalated silver atoms become ordered in a structure that produces a \ensuremath{\surd}3a\ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3a\ifmm…
Abstract The degrees of swelling of rigid aromatic polyamide networks in various solvents, nonsolvents, and solvent mixtures were used to determine their solubility parameters. This was made possible because of the amorphous nature of the rigid networks and the low levels of intersegmental H‐bonding. The solubility pa…
Abstract The effect of low dose (1–20 Mrad) γ‐irradiation on five fluoropolymers (PVF, PVDF, ETFE, FEP, PFA), differing in fluorine content and chain structure, was studied. The radiation effect, reflected by changes in thermal and mechanical properties, as well as NaOH etched surface morphology, was investigated. The…
We present the results of a study of solid–fluid phase equilibria in systems of hard dumbbells for three values of the dumbbell bond length. Monte Carlo simulations were used to calculate the equation of state and Helmholtz free energy. Four orientationally ordered solid phases have been considered—the α-N2 structure…
We demonstrate that ${\mathrm{CdS}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Se}}_{\mathit{x}}$ nanocrystals embedded in glass suffer compressive strain which increases as the crystallite radius decreases. A model based on the dependence of the cluster surface free energy on the surface-to-volume ratio explains…
The optical spectra of actinide ions in the compound AnCl3 and doped into single-crystal LaCl3 were interpreted in terms of transitions within 5fN configurations. Energy-level calculations were carried out using an effective-operator Hamiltonian, the parameters of which were determined by fitting experimental data. At…