The crystal structures of tetrapyridine copper(I) perchlorate and tetrapyridine silver(I) perchlorate at 250 K
c 16 H" 6 AuBr,N or [
Materials Literature
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Electrical properties and non-stoichiometry in ZnO single crystals
The electrical conductivity and the Hall effect are investigated in the temperature region from 77 to 1000 K on undoped ZnO single crystals grown by vapour phase transport. The growth conditions were systematically altered to get crystals with definite non-stoichiometry. The electrical properties are related to these…
A critical examination of the law of approach to saturation. I. Fit procedure
The numerical influence of different terms in the law of approach to saturation is tested applying a least square procedure on a variety of sets of synthetical data (256 I(H) points) which are generated using the formula I = I8[1 − (A/H) − (B/H2) − (C/H3)] + χH + D√H. Graphical methods are compared with the fitting pr…
JCPDS-International Centre for Diffraction Data
correspondence with the authors. In a few cases the problems are not resolved and such entries are either flagged or omitted.
Low-temperature thermal conductivity of amorphous silica
In order to understand the importance and limitations of the role of low-temperature thermal-conductivity data in understanding amorphous glasses, we have used the two-level tunneling-state model to generate fits to such data. A variety of densities of states have been utilized, including the forms previously suggeste…
Charge distribution in potassium graphite
The $c$-axis charge distribution in higher-stage potassium graphite has been obtained from an analysis of carbon $1s$ core-electron binding-energy spectra. The highly localized distribution of transferred charge in the bounding layer effectively screens the positive intercalant ions. The interior layers are thus graph…
Observation of large room-temperature coercivity in melt-spun Nd0.4Fe0.6
An intrinsic room-temperature coercivity of 7.45 kOe has been found in melt-spun Nd0.4Fe0.6; this value is the largest ever reported for a rare-earth–iron alloy. A significant correlation was found between quench rate and coercivitiy, suggesting that the quenched alloys consist of fine crystallites or clusters, whose…
Bis(triethylammonium) hexachlorostannate (IV): crystal structure and hydrogen bonding
The crystal structure of (Et 3 NH) 2 SnCl 6 at room temperature consists of a monoclinically distorted antifluorite packing of Et 3 NH + and SnCl 6 2− ions. Each anion has two cations centrosymmetrically associated with it through bifurcated hydrogen bonds to four of the Cl atoms, leaving two of the six chlorines unen…
Studies of chemiluminescence in boron atom reactions with O2, SO2, N2O, NO2, and H2O2
Chemiluminescence has been observed in the single collision reaction of boron atoms with O2, SO2, N2O, NO2, and H2O2. The experiments were performed in a beam-gas apparatus using photon counting to detect the optical signals. The electronically excited A 2π state of BO was observed in all the reactions. In addition, t…
Structure of N-acetyl-L-cysteine: X-ray (T = 295 K) and neutron (T = 16 K) diffraction studies
JV-Acetyl-L-cysteine, C5H9N03S,Afr= 163-20,crystallizes in the space group PI, with a = 5-766 (1), b = 6-433 (1), c = 5-014(1) A, a= 102-80(2), /} = 102-77 (1), y = 95-81 (1), Z = 1 and final R^F 7 ) = 0-024 for a total of 1232 independent reflections, at T -16 K. The structure was first deduced from * Structure and C…
Theory of hydrogen absorption in metal hydrides
A theory of hydrogen absorption by metal hydrides is formulated in the mean-field approximation. The distinction between the true saturation and an incipient saturation is emphasized. It is shown that the incipient saturation is a manifestation of the effect of $d$-band structure upon the absorption of hydrogen. Absor…
One-dimensional model for a crystal with displacive modulation
As a model for a crystal with displacive modulation a classical linear chain is discussed with up to third-neighbor interaction. This system has an infinite number of stable equilibrium configurations separated by high barriers. It has a zero-frequency phonon mode, a low-lying phason branch, and an amplitude mode.
Electron-spectroscopic studies of theCuxPd1−xalloy system: Chemical-shift effects and valence-electron spectra
The valence- and core-electron spectra have been investigated for a series of ${\mathrm{Cu}}_{x}{\mathrm{Pd}}_{1\ensuremath{-}x}$ alloys by means of ESCA (electron spectroscopy for chemical analysis). In the dilute limits a subtraction method is applied to derive the contribution of the low-concentration components to…
Electrical-resistance behavior of Ca at high pressures and low temperatures
The electrical-resistance behavior of Ca is studied from 2 to 300 K at various pressures up to 440 kbar using a clamp-type sintered diamond-tipped opposed-anvil apparatus. It is found that the electrical resistance of Ca at room temperature increases monotonically as a function of pressure and reaches a maximum at abo…
Transport and optical properties ofTi1+xS2
We report measurements of the electrical resistivity, Hall coefficient, magnetoresistance, thermoelectric power, infrared reflectivity, and $c$-axis lattice parameter of single crystals of titanium disulfide ${\mathrm{Ti}}_{1+x}{\mathrm{S}}_{2}$ with varying degrees of nonstoichiometry. The strong correlations we find…
Conducting complexes of polyphenylene sulfides
Poly(p-phenylene) sulfide, poly(m-phenylene) sulfide, and the newly synthesized polymer poly(thio-2,8-dibenzothiophenediyl) have been treated with strong electron acceptors (AsF5, SbF5) to form conducting complexes with p-type electronic conductivities up to 3 S/cm. Near IR to UV absorption spectra and temperature-dep…
Enhanced Raman scattering by molecules adsorbed at the surface of colloidal spheroids
Equations are derived and calculations are presented for the electrodynamic mechanism of enhanced Raman scattering by molecules at the surface of prolate and oblate spheroids in the small-particle limit. The molecules may be arbitrarily distributed; the particles may be arbitrarily oriented. Calculations are presented…
Phonon Optics and Phonon Propagation in Semiconductors
Recent experiments involving the propagation of extremely high frequency, short-wavelength acoustic phonons in semiconductors are described. Such phonons, which play an important role in thermal energy transpor and nonradiative recombination processes, can be used as sensitive microscopic probes of electronic, defect,…
On the determination of electrical conductivity in polyethylene
There are significant differences in the field dependence of conductivity in low-density polyethylene as reported by various investigators. These differences are attributable partly to the presence of different kinds of impurities in variable concentrations in polyethylene samples of various origin, but are mainly due…
EPR spectra of Cr3+centres in crystals of Cs2CdCl4
When crystals of Cs 2 CdCl 4 (K 2 NiF 4 -type structure) are doped with Cr 3+ a number of different impurity centres are formed which are readily distinguishable by EPR spectroscopy. The doped crystals contain both compensated and uncompensated Cr 3+ centres. The resonances from the uncompensated Cr 3+ exhibit axial s…