Materials Literature
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Values for the ionization energies of the neutral actinides have been derived by utilizing interpolated spectral properties of these atoms. The results in electron volts are Ac: 5.17(12); Th: 6.08(12); Pa: 5.89(12); U: 6.05(7); Np: 6.20(12); Pu: 6.06(2); Am: 5.993(10); Cm: 6.09(2); Bk: 6.30(9); Cf: 6.41(10); Es: 6.52(…
The effect of uniaxial stress on the first-order Raman spectra of the cubic crystals, Ca${\mathrm{F}}_{2}$, Ba${\mathrm{F}}_{2}$, and ${\mathrm{Bi}}_{12}$Ge${\mathrm{O}}_{20}$ is studied at $\ensuremath{\sim}15$ \ifmmode^\circ\else\textdegree\fi{}K using a quantitative-stress cryostat. Both Ca${\mathrm{F}}_{2}$ and Ba…
The polarized light scattering spectrum from a dilute solution of spherical macromolecules is customarily interpreted on the basis of independent particle diffusion. However, it is known that diffusion in such a system is governed by a many particle diffusion equation with cross-diffusion coefficients Dij that depend…
We have observed the EPR spectra of As acceptors in both natural Mo${\mathrm{S}}_{2}$ crystals ($2H$ polytype) and in synthetic Mo${\mathrm{S}}_{2}$ crystals ($3R$ polytype). The $g$ values of the resonance signals show that the As acceptors are associated with a band that has ${d}_{{z}^{2}}$ orbital character. Energy…
Luminescence studies are reported on compounds M(IV)X2P: M is Si, Ge, Sn, Pb; X is F, Cl, Br, I, OH, benzoate; P is etioporphyrin or octaethylporphin. (One tetraphenylporphin is reported for comparison.) We find fluorescence yields 2 × 10−1 ≥slant φf ≥slant 2 × 10−4; phosphorescence yields 7 × 10−2 ≥slant φp ≥slant 3…
X-ray photoelectron spectra (XPS) of the valence bands of crystalline and amorphous As, Sb, and Bi have been measured. The results are compared with band-structure calculations for the crystalline materials. A splitting, $\ensuremath{\Delta}E$, of the "$s$-like" peak for the crystalline phase disappears in the amorpho…
The reaction kinetics of U + 3/2 H2⇄UH3 was studied with fine powders on an ultrahigh-vacuum microbalance. The kinetics were found to be first order with respect to uranium for the hydriding reaction and nearly zero order with respect to uranium hydride for dehydriding. A new reaction mechanism is proposed to account…
The polarized Stokes and anti-Stokes Raman spectrum of amorphous ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$ has been measured at several temperatures in the range 20-448 \ifmmode^\circ\else\textdegree\fi{}K with a He-Ne laser, and at room temperature with a c.w. dye laser. Using the Shuker-Gammon data-reduction method, the…
The principle of a new electrochromic display based on an oxidation-reduction reaction of an organic compound of the viologen family is described. The result is a display having a built-in memory, high contrast, a low switching voltage, and a low mean power consumption.
The resonance aspect of chemical bonding is extended to solids with particular emphasis on its consequences for structural and vibrational properties. It is shown, for example, that the square of the infrared effective charge is proportional to the high-frequency dielectric constant in resonance-bonded systems. The IV…
Measurements of the magnetic susceptibility, magnetic moment and specific heat of holmium phosphate, HoPO 4 , show that there is a magnetic phase transition to an antiferromagnetic state at a Neel temperature of 1.39 K. The measurements indicate that the g value of the Ho 3+ ion is highly anisotropic with g c =16.0, g…
Surface-state transitions on ordered silicon (100)2\ifmmode\times\else\texttimes\fi{}1 and (111)7\ifmmode\times\else\texttimes\fi{}7 surfaces have been observed by electron energy-loss spectroscopy. The surface transitions were identified by comparing the clean ordered surfaces with clean disordered surfaces, and with…
A computer study of a tetrahedrally coordinated random-network structure is reported as a model for amorphous Si or Ge. A previous model is refined to produce equal near-neighbor distances; it is more carefully statistically characterized and the coordinates of each individual atom are now known. The radial distributi…
EPR investigations of ${\mathrm{Ag}}^{2+}$ in the series of isomorphous hosts SrO, CaO, and MgO show that the low-temperature Jahn-Teller effect is static for SrO: ${\mathrm{Ag}}^{2+}$, predominantly static but intermediate to the dynamic effect for CaO: ${\mathrm{Ag}}^{2+}$, and predominantly dynamic but slightly int…
Abstract A modified Eyring rate expression based on an asymmetrical potential energy barrier is used to predict the onset of plastic yield in glassy polymers. Equations for the prediction of plastic yield delay times in creep and yield stresses in constant rate of strain testing are developed and compared to experimen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry and biology of vitamin B6. 32. Selective modification of the .alpha.4 position of pyridoxol. 4-Vinyl analog of pyridoxal, a potent antagonist of vitamin B6W. Korytnyk, G. B. Grindey, and B. LachmannCite this: J. Med. Chem. 1973, 16, 7, 865–867Publication Date (Prin…
Sodium diarsenate at room temperature is monoclinic with lattice parameters a = 5.969(1), b = 10.126(1), c = 12.272(3) Å and β = 92.87(2)°. There are four formula units per cell with space group C2/c. The structure was refined by full-matrix least-squares to a final R value of 0.027 utilizing 1157 reflections measured…
In this second contribution the Fraunhofer diffraction patterns from apertures of the form of an equilateral triangle, a square, a regular pentagon, a hexagon and an octagon are compared with the calculated maps of the intensity distribution. For each shape of the aperture the first few maxima and minima of the intens…
(1973). Atomizing molten metals — a review. Canadian Metallurgical Quarterly: Vol. 12, No. 3, pp. 309-322.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction of phenyl isocyanate with N-methyl-2-pyrrolidinoneReinhard Richter and Henri UlrichCite this: J. Org. Chem. 1973, 38, 15, 2614–2617Publication Date (Print):July 1, 1973Publication History Published online1 May 2002Published inissue 1 July 1973https://pubs.acs.org/do…