Materials Literature
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Fluorescence quenching effects caused by multipolar energy-transfer interactions between rare-earth ions are examined. Transfer between remote ions by way of transitions that are matched in energy appears to be essentially dependent upon concentration alone (e.g., Sm3+ self-quenching) while transfer by non-resonant me…
Abstract Using synthetic near-ideal graphite obtained by hot-pressing and annealing pyrolytic material, we have prepared graphite nitrates from the first to the fourth sequence, under controlled conditions. For the first sequence compound, present determinations on form I (room temperature) agree with previous publica…
The infrared spectrum of hydrogen bonded HN3 dimers in solid nitrogen has been determined. A dimer band at 387 cm−1, assigned to the torsional distortion of the hydrogen bond, indicates the dimer has an open, not a cyclic structure. The hydrogen bond bending force constant is 0.09 mdyn/Å. The hydrogen bond frequency s…
The magnetocrystalline anisotropy constant ${K}_{1}$ of iron was determined from static torque measurements on a {001} single-crystal disk at fields between 3000 and 18 000 Oe, and at temperatures between 77 and 900\ifmmode^\circ\else\textdegree\fi{}K. It was found that (i) $\frac{(\frac{\ensuremath{\partial}{K}_{1}}{…
(NH 4 ) 2 TeBr 6 and Cs 2 TeBr 6 crystals have the cubic K 2 PtCl 6 structure with space group: [Formula: see text] with a 0 = 10.728 ± 0.003 Å and 10.918 ± 0.002 Å respectively. The positional coordinate of the bromine atom, and the anisotropic temperature factors of all atoms in the unit cell, have been refined for…
Paramagnetic resonance measurements have been carried out at 78° and at 4°K on Cu2+ ions diluted in single crystals of CdWO4, ZnWO4, and MgWO4. The g factors and the hyperfine interaction with the copper nucleus have been determined. From this experimental data the ground-state wavefunction of the Cu2+ ion has been co…
ESR and optical measurements have been made on the lowest triplet state of a series of phenyl s-triazines and polyphenyl benzenes. The features of the phosphorescence spectra and the value of the zero-field splitting parameters of these azines and their hydrocarbon analogs leads to the assignment of the lowest triplet…
The ferroelectric behavior of triglycine sulfate, which can be considered the best example of a nearly ideal second-order-transition ferroelectric, has been analyzed. Accurate measurements of the temperature dependence of spontaneous polarization and dielectric constant in the vicinity of the phase transition from the…
The two-vibrational-mode model proposed by Toyozawa and Mahr to account for the Urbach rule is considered both in the semiclassical approximation and in the full quantum theory. The semiclassical line shape accounts for both the exponential Urbach tail and the central Gaussian region of the absorption band. Quantum mo…
Photoelectric yield and energy distributions are given for clean-cleaved and cesium-covered (111) surfaces of silicon and germanium. A monolayer of cesium lowers the work function of each to \ensuremath{\sim}1.6 eV and reveals detailed structure in both yield and distributions. This structure is directly related to th…
Optical absorption in stoichiometric and reduced, semiconducting single crystals of SrTi${\mathrm{O}}_{3}$ has been measured in the region 0.4-5 \ensuremath{\mu} at room temperature and 77\ifmmode^\circ\else\textdegree\fi{}K. Reduced crystals show a rapid increase of absorption with increasing wavelength beyond 0.6 \e…
By representing the effective-tension term of a dislocation (string model) as a power series in displacement gradients, and retaining the first nonlinear term, expressions for the amplitudes of the second and third harmonics of an ultrasonic wave introduced into a solid containing mobile dislocations are obtained. In…
The lattice parameters, atomic volume, nearest-neighbor interatomic distance, axial ratio, and coefficients of thermal expansion of zirconium are reported over the temperature range 4.2 to 1130\ifmmode^\circ\else\textdegree\fi{}K. The data were obtained from single crystals, using a precision x-ray diffraction techniq…
The electrical conductivity and the Seebeck effect are measured in the temperature region of 100 to 1300\ifmmode^\circ\else\textdegree\fi{}K in NiO doped with Li. From the results it is concluded that the mobility of the charge carriers involves no activation energy. The temperature dependence of the conductivity is a…
Viscosity and density data were obtained for several series of alkali aluminosilicate melts between 1200° and 1700°C with a counterbalanced sphere viscometer. Property comparisons are presented as functions of the SiO2 content, Na2O content, and constant Al/Na ratios at 1500° and 1700°C. The viscosity and expansion in…
Recently, Wachtman and his colleagues showed that a good description of the temperature dependence of the Young's modulus of several oxides is $Y={Y}_{0}\ensuremath{-}{b}_{1}T\mathrm{exp}(\ensuremath{-}\frac{{T}_{0}}{T})$ where ${Y}_{0}$ is the modulus at absolute zero and $b$ and ${T}_{0}$ are constants. Wachtman and…
M\"ossbauer spectra of the perovskite series ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Fe}{\mathrm{O}}_{y} (0.0<~x<~1.0);y\ensuremath{\lesssim}3)$ with $^{57}\mathrm{Fe}$ as the photonemitting and -absorbing nucleus were analyzed. The N\'eel temperature of antiferromagnetic LaFe${\mathrm{O}}_{3}$…
Abstract Several series of compounds were prepared from oleyl alcohol which may prove useful as lubricants and plasticizers. The reactions involved addition to the double bond and replacement of the hydroxyl moiety. One series of compounds is characterized l‐R艂, 9(10)R octadecane where l‐R艂 signifies the replacement o…
We deformed polycrystalline Fe-Be alloys to see how grain size affects the flow stress of a metal which deforms primarily by mechanical twinning. At high beryllium contents in supersaturated solid solution, low temperatures and coarse grain sizes, the flow stress did not simply increase linearly with the grain size va…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Kinetics of Formate Ion Pyrolysis in Alkali Halide Matrices1,2K. O. Hartman and I. C. HisatsuneCite this: J. Phys. Chem. 1966, 70, 4, 1281–1287Publication Date (Print):April 1, 1966Publication History Published online1 May 2002Published inissue 1 April 1966https://pubs.a…