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The elastic constants of zirconium carbide and titanium carbide were determined over the temperature range of 4.2° to 298°K using a pulsed-ultrasonic phase comparison technique, and are compared to previously determined values for uranium carbide. Since these carbides are of the NaCl structure, only three independent…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAbsorption Spectra of Octahedral Lanthanide HexahalidesJack L. Ryan and Chr. Klixbüll JørgensenCite this: J. Phys. Chem. 1966, 70, 9, 2845–2857Publication Date (Print):September 1, 1966Publication History Published online1 May 2002Published inissue 1 September 1966https://pu…
Fine metallic particles exhibit a peak of optical absorption around the frequency of the plasma mode. The absorption is broadened by coupling of the plasma oscillation with the individual electronic states which are quantized in discrete levels. Thus the broadening should not be interpreted as the resistance of free e…
The effects of couple stresses in fluids are considered. Linearized constitutive equations are proposed for force and couple stresses. A series of boundary-value problems are solved to indicate the effects of couple stresses as well as for experiments measuring the various material constants. It is found that a size e…
Abstract Durch Reduktion der Methoxycarbonylgruppen des Mesoporphyrin‐dimethylesters ( 4a ) wird das bisher unbekannte 1.3.5.8‐Tetramethyl‐2.4‐diäthyl‐6.7‐dipropyl‐porphin ( 5c ) erhalten. 5c läßt sich wie Octaäthyloporphin ( 7a ) als Kupferkomplex mit Hilfe der Vilsmeier‐Reaktion an einem meso ‐Kohlenstoffatom formyl…
Abstract A detailed analytical and kinetic study of the thermal decomposition of monosilane in the temperature range 375 to 430 °C and the initial pressure range 35 to 230 mmHg has been conducted. The gaseous products in the very early stages of the reaction are hydrogen, disilane and trisilane. In addition, later in…
Abstract The frequencies of the normal modes of vibration of lead telluride propagating in certain symmetric directions have been determined by inelastic neutron scattering techniques. The results have been used to deduce the parameters of rigid ion models and of shell models for the interatomic forces. The latter mod…
The Brillouin scattering spectra of crystalline quartz, fused quartz and Pyrex glass have been observed. The crystalline quartz spectrum contains three doublets corresponding to one longitudinal and two transverse acoustic modes, whereas the spectra of used quartz and Pyrex glass have one longitudinal and one transver…
The optical spectrum of Re4+(5d3) has been studied at 4.2°K in single crystals of K2PtCl6 and Cs2ZrCl6. The spectrum is characterized by extremely narrow lines in the region from 8500 to 36 000 cm−1. Vibrational structure is observed which is assigned to the odd modes of the ReCl62− complex. A crystal-field analysis o…
Single crystals of potassium sulfamate, KNH 2 SO 3 , enriched in the isotope 15 N, were irradiated, and examined at 77° K by electron spin resonance. Two intermediates, neither of which are present on examination at 300 °K, have been identified as NH 2 and NH 2 SO 3 . A possible radiolysis mechanism is discussed.
The magnetic susceptibilities of the monophosphides of V, Cr, Fe, and Co have been measured from 4.2\ifmmode^\circ\else\textdegree\fi{}K to room temperature. They were all found to be weakly paramagnetic. The previously reported metamagnetic transition in the MnP was confirmed, whereas none of the other compounds exhi…
First-order and second-order (in strain) magnetoelastic effects in yttrium iron garnet (YIG) have been studied using a pulsed ultrasonic technique and have been interpreted using finite-deformation magnetoelastic theory. Small-amplitude plane-wave modes in 100>, 110>, and 111> directions in uniformly magnetiz…
We have constructed to high order ($l=30$) all the linear combinations of spherical harmonics which transform as the identity representation of the full cubic group ${O}_{h}$. These are used with Mueller's inversion scheme to obtain the radius vectors of the palladium $s$-band surface from the de Haas-van Alphen areas…
The relative strengths of the hydrogen bonds in kaolinite-alkali salt-water systems control kaolinite-salt interactions. A new technique for intercalation results in formation of a kaolinite-salt complex free of excess salt.
A mechanism for vacancy generation in perfect crystals is proposed in which it is assumed that the progenitor for color-center formation is a dissociating $X_{2}^{}{}_{}{}^{=*}$ (excited) molecule: if this molecule is initially created, or subsequently placed, in an excited vibronic, predissociative, or repulsive stat…
The thermoluminescence (TL) of semiconducting diamonds was found to be composed of blue-emitting (at 150 and 260\ifmmode^\circ\else\textdegree\fi{}K) and red-emitting peaks (at 175 and 285\ifmmode^\circ\else\textdegree\fi{}K). The red peaks could be excited by light of wavelengths up to about 650 m\ensuremath{\mu} (1.…
A variety of phonon-gas phenomena in nonmetals are discussed in a unified manner using a set of macroscopic equations developed from the solution of the linearized phonon Boltzmann equation. This set of macroscopic equations, appropriate for the description of a low-temperature phonon gas, is solved for a cylindrical…
The ionic thermoconductivity (ITC) method, consisting of the study of the thermally activated release of dielectric polarization, is studied in great detail in alkali halide crystals. The (divalent metal ion, cation vacancy) dipoles give rise to an ITC band below 0\ifmmode^\circ\else\textdegree\fi{}C, whose area is pr…
The linearized Boltzmann equation for the pure phonon field may be solved formally in terms of the eigenvectors of the normal-process collision operator. This representation is particularly convenient as a basis for solutions, since in the isotropic dispersionless case the temperature deviation $\ensuremath{\delta}T$…
It is reported that a hitherto unexplained optical transition in ZnTe is due to oxygen substituting isoelectronically for Te. A classification of isoelectronic traps into isoelectronic donors and acceptors is made. One striking difference between these two classes is apparent in the phonon sidebands of the $J=1$ and $…