Materials Literature
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A computer program has been written with the aim of calculating powder patterns without the use of crystallographic tables. This has been achieved by deriving all symmetry information such as general equivalent positions from the Hermann-Mauguin space-group symbols, by calculating automatically the multiplicities of s…
A review is given of the nonlinear optical properties of 20 uniaxial crystals: KDP, DKDP, ADP, CDA, DCDA, RDA, RDP, LiIO 3 , LiNbO 3 , Ag 3 AsS 3 , Ag 3 SbS 3 , AgGaS 2 , AgGaSe 2 , ZnGeP 2 , CdGeAs 2 , GaSe, CdSe, HgS, Se, Te. Typical applications of these crystals are indicated.
The thermal conductivity, kappa , has been measured as a function of temperature between 2K and 100K of polycarbonate (PC), polyvinyl chloride (PVC) isotactic polypropylene (PP), polyoxymethylene (POM), and polyethylene terephthalate (PET). For the latter three systems the variation of kappa on extrusion has also been…
Transient nuclear magnetic resonance (NMR) measurements on 3He, generated by β decay and contained in aging titanium tritide (TiH1.8), have been carried out. The experiments were conducted over a period of about three years during which the rate of helium evolution from the sample abruptly increases. Qualitative analy…
Multiple-order Raman scattering was observed in CsI doped with Mn$\mathrm{O}_{4}^{}{}_{}{}^{2\ensuremath{-}}$. The Raman spectra consist of a series of sharp, equally spaced lines due to multiple-order scattering from the totally symmetric mode of Mn$\mathrm{O}_{4}^{}{}_{}{}^{2\ensuremath{-}}$. Each sharp line in the…
Generalized susceptibilities, ${\ensuremath{\chi}}^{0}(\stackrel{\ensuremath{\rightarrow}}{\mathrm{q}})$, have been obtained for the $1T$ polymorphs of both Ta${\mathrm{S}}_{2}$ and Ta${\mathrm{Se}}_{2}$ from their Korringa-Kohn-Rostoker band structures. Peaks are found which correspond to the charge-density-wave (CDW…
From Knudsen effusion mass spectrometric examination of reactions of the type M(g)+MO(g) =M2O(g), 2MO(g) =M2O2(g), and 2MO(g) =MO2(g)+M(g), the atomization energies ΔH°0 (kcal/mole) of the following new species have been estimated: Eu2O(g), 174±12; Gd2O(g), 236±10; Tb2O(g), 243±12; Ho2O(g), 216±14; Lu2O(g), 266±14; Eu…
The heat capacity of $\ensuremath{\beta}$-alumina containing Li, Na, K, Rb, and Ag as the diffusing ion is found to be a strong function of the ion at temperatures between 1.3 and 40 K. The excess heat capacity above a Debye contribution for the host lattice of Al and O ions is compatible with the low-frequency modes…
In ionic charge-transfer salts which have segregated stacks of organic donor ($D$) and acceptor ($A$) molecules, the major feature of the classical electrostatic interactions is the strong repulsion between like charges along the stacks. Two ways are described by which the magnitude of this repulsion may be decreased:…
Electron drift mobilities have been observed in ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$ crystals along the molecular direction by transient photoconductivity techniques. The mobility is 1.0 ${\mathrm{cm}}^{2}$/V sec, independent of temperature from 207 to 465 K. This result is consistent with a trend among inorganic and…
The temperature dependence of the spin-lattice relaxation time of $F$ centers in KBr is investigated between 6 and 15\ifmmode^\circ\else\textdegree\fi{}K. The observed values of ${T}_{1}^{\ensuremath{-}1}$ can be fitted by a law of the form ${T}_{1}^{\ensuremath{-}1}=B{T}^{7}+C{T}^{9}$ with $B$ and $C$ independent of…
Singular instabilities at crystal growth interfaces of group-IV and III-V semiconductors lead to as-grown surfaces optical devices, however, requirethe achievement of smoth planar layers. We consider the stability of surfaces with respect to singular instabilities and show that stable planar growth interfaces occur at…
The stacking sequence and interplane and interlayer separation of $2H\ensuremath{-}\mathrm{M}\mathrm{o}{\mathrm{S}}_{2}$ and $2H\ensuremath{-}\mathrm{N}\mathrm{b}{\mathrm{Se}}_{2}$ are determined by the dynamical low-energy-electron diffraction approach. Although lateral reconstructions corresponding to alteration in…
The resistivity and activation energy $\ensuremath{\Delta}E$ in $\ensuremath{\rho}={\ensuremath{\rho}}_{0}\mathrm{exp}(\frac{\ensuremath{\Delta}E}{\mathrm{kT}})$ of flash evaporated amorphous ${\mathrm{As}}_{2}$${\mathrm{Te}}_{3}$ films were found to decrease gradually with increasing pressure until $\ensuremath{\rho}…
Monolayer structures and epitaxial growth of vapor-deposited crystalline phthalocyanine films on single-crystal copper substrates were studied using low-energy electron diffraction. At monolayer coverage, ordered layers of copper-, iron-, and metal-free phthalocyanines were observed on both Cu(100) and Cu(111). With i…
The authors have measured the photoelectron distribution curves of single-crystal faces of copper, silver and gold using photon energies of 11.83, 16.85 and 21.22 eV. The photoelectrons are collected in a narrow cone normal to the surfaces. The results show the existence of occupied surface states in the L gaps of eac…
A Monte Carlo method based on Curgenven and Duncumb's treatment (1971) is described. It is shown that the predictions of the model agree well with experimental backscattered electron energy distributions and phi ( rho z) curves. The model is used to generate phi ( rho z) curves for a wide range of analytical condition…
The $^{31}\mathrm{P}$ chemical-shift tensors $\stackrel{\ensuremath{\leftrightarrow}}{\ensuremath{\sigma}}$ have been determined as a function of temperature on going through the ferroelectric phase transition in a single crystal of K${\mathrm{D}}_{2}$P${\mathrm{O}}_{4}$, and an abrupt change in $\stackrel{\ensuremath…
Incident electrons follow a parabolic trajectory when an electric field is applied normal to the surface of a metal crystal with force vector directed outwards. Under appropriate conditions touching trajectories may be neglected, and electron-surface-plasmon scattering is dominated by trajectories with closest approac…
Semi-transparent films of gold, copper, silver and aluminium prepared by vacuum deposition techniques show filter properties of lower transmission and higher reflection in the near infrared region than in the visible region. These films are therefore used as coatings for solar control glasses and produced in large vac…