Materials Literature
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Experiences on crystal growth of calcite doped with Pb2+ using the method of travelling solvent zone melting (TSZM) are reported. Optical absorption, polarized luminescence, excitation spectra, decay times and relative quantum yields of the Pb2+ centres are studied in their temperature dependence. The properties found…
A new continuously tunable color filter, which uses smectic A(*) liquid-crystal half-wave plates, is described and experimentally demonstrated. Multiple-stage Lyot filters with broad tunability and high finesse can be constructed with this design. The transmission characteristics of a single-stage filter, which is con…
We have developed a site-selective laser method to study the aggregation kinetics of defect sites as a result of heat treatment in ${\mathrm{EuF}}_{3}$-doped ${\mathrm{CaF}}_{2}$ crystals. The crystals contain ${\mathrm{Eu}}^{3+}$ in four dominant defect sites and one minor site that differ in the number of nearby dop…
The temperature dependence of Raman spectra of lithium diborate (Li 2 B 4 O 7 ) was measured at temperature range from 300 K to 900 K. At room temperature, 12 A 1 , 12 B 1 , 15 B 2 and 22 E modes were observed by various scattering geometries. No soft mode was observed in the above temperature range, implying that no…
We report calculations of the electronic structure of a model of ${\mathrm{TiO}}_{2}$ which contains oxygen vacancies. The model uses the full tight-binding model of Vos. We use a screened Coulomb potential and a soft positive core to describe the oxygen vacancy. We study the electronic density of states as a function…
The linear muffin-tin orbitals (LMTO) method is used to calculate the self-consistent spin-polarized electronic structures of ${\mathit{R}}_{2}$${\mathrm{Fe}}_{14}$B (R=Y,Nd) compounds. The present results are compared with those of an earlier non-self-consistent calculation. The calculated results are in good agreeme…
The two tin oxides, SnO and ${\mathrm{SnO}}_{2}$, are not easily distinguished by their core x-ray photoelectron spectroscopic regions, but have significantly different valence-band regions. In addition, significant differences exist in the separations between the near-core region and the valence-band region. These di…
Low-temperature (10–300 K) dielectric and pyroelectric properties of morphotropic-phase-boundary lead-barium-niobate tungsten-bronze ferroelectric single crystals have been investigated. Strong ‘‘Debye-like’’ dielectric dispersion, along a nonpolar direction (perpendicular to the polarization direction), has been obse…
An analysis is presented of the growth of silver aggregates in the size range 10--200 \AA{} on an amorphous carbon substrate (a-C). It is found that growth at this submicroscopic scale exhibits the main statistical properties observed on a scale of ${10}^{\mathrm{\ensuremath{-}}3}$--1 mm in the patterns formed when a…
We present the results of spectroscopic studies of the electronic structure of the conjugated polymer poly(2,5-thienylene vinylene). Photoexcitation above the band gap at 1.8 eV gives rise to two transient absorption peaks at 0.44 and 1.0 eV that are associated with bipolarons that live for times of order a few millis…
In order to clarify the role of hydrogen in diamond synthesis using a microwave plasma in a CO/H2 system, carbon films were grown by varying hydrogen mole fractions in a CO/H2/He microwave plasma. The correlation between film properties and plasma species was investigated through film characterization and plasma emiss…
The dielectric relaxation function is defined as the transient current generated by the application of a unit voltage. In analogy with viscoelasticity, a second relaxation function can be defined as the transient voltage generated by the application of a unit current. Each of these functions generates its own distribu…
The uniaxial magnetic crystalline anisotropy of Pd 1- x Fe x in tetragonal L1 0 -type ordered phase (\(0.38\lesssim{x}\lesssim0.50\)) was obtained from magnetization curves of quasi-single crystal samples in a magnetic field up to 100 kOe. The first anisotropy constant K u1 at 4.2 K of stoichiometric composition ( x =…
High-temperature gaseous equilibria among the species Th, ThCl, ThCl2, and ThCl3 were studied by mass spectrometry over broad temperature ranges; both enthalpy and entropy data were derived by the second law procedure. In addition, the sublimation of ThCl4 was studied by the torsion-effusion method and the thermodynam…
The photodissociation of axial ligands from six-coordinate nickel(II) porphyrins in solution has been studied by transient absorption spectroscopy with subpicosecond resolution. Our observations indicate that the deligation process takes place during the first several picoseconds following optical excitation of the ma…
Calculations of the propagation of high-energy phonons introduced into a crystal at T=0 K are presented. The phonons are assumed to undergo elastic scattering and anharmonic decay processes. We show that in addition to the ``quasidiffusion'' component to the phonon propagation (discussed previously by Levinson and co-…
Spectroscopic measurements of fluorescence and absorption in an erbium-doped fiber permit the evaluation of the Stark-level energies of the (4)I(15/2) and (4)I(13/2) manifolds in Er:glass. The data permit the allocation of the individual laser transitions associated with the room-temperature gain spectrum of erbium-do…
The laser fluorescence excitation spectra and single vibronic level fluorescence spectra have been measured for jet-cooled tropolone (–OH) and tropolone (–OD). The ν′11(a1), ν12(a1), and ν′19(a2), modes have been newly identified in the excitation spectrum of tropolone (–OH), in addition to the previously observed ν13…
Raman scattering measurements have been carried out on poly(propylene oxide) complexed with NaCF3SO3 salt of concentration O:M=30:1 (where O:M is the PO:Na ratio) over a temperature range of 186–360 K in order to study ion–ion associations of the dopant salt and their temperature dependence. Splitting of the symmetric…
The gas-phase composition at the surface of a growing diamond film was measured as a function of the initial methane (CH4) fraction and, for a 2% methane fraction, as a function of added oxygen (O2). The results were modeled with a one-dimensional reactor flow code that includes diffusion and detailed chemical kinetic…