Materials Literature
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Abstract The synthesis and isolation of heptafulvene ( 1 ) and sesquifulvalene ( 2 ) is reported: Acetoxy‐tropylium‐fluoroborate ( 10 ) may be prepared by addition of tropone to acetyl‐fluoroborate at low temperatures. The tropylium salt reacts easily with methyllithium and sodium cyclopentadienide to give the acetoxy…
Abstract The substituted benzylideneanilines 2–7 and the respective 3 H ‐indoles 9–14 have been synthesized. A comparison of their electronic absorption spectra shows it is likely that 4‐nitrobenzylidene‐4′,‐dimethylaminoaniline ( 6 ) has a planar conformation.
Terbium reacted with DNA and chromatin to form a complex in which terbium acted as a sensitive fluorescent probe. By measuring the narrow-line emission of Tb-3+ when DNA is selectively excited, the relative amount of Tb-3+ bound to the DNA can be calculated. Terbium was bound to DNA until one Tb-3+ was present for eac…
It is argued that, in a process involving ejection of an inner shell electron by an unpolarized beam of photons and subsequent atomic reorganization via Auger ejection, the two ejected electrons can be strongly correlated in direction. In general, the detailed form of the correlation will depend on both photoionizatio…
A detailed investigation is reported of electrical properties of polycrystalline PbZrO3 samples around the points of phase transitions from the antiferroelectric state (AFE) to the ferroelectric (FE) and paraelectric (PE) states. The influence is studied of a constant electrc field on the phase transitions AFE ⇄ FE an…
Measurements of the ultrasonic wave velocities at 30 to 50 MHz frequencies reveal very significant effects of dissolved hydrogen on the elastic shear moduli, C′ = (C11 – C12)/2 and C44, of the group V b.c.c. transition metals. In all cases C′ decreases with increasing hydrogen solute, whereas C44 increases and the bul…
The fluorescence, excitation, and reflection spectra of ZnS:Ag phosphors at room temperature and at 77°K were measured in detail. A number of excitation bands characteristic of Ag+ center were found in the spectral region from about 3400 to 5000 Å. The ligand-field analysis of the excitation spectra was performed, bas…
Photo yield was measured as a function of incident angle for polarized light incident through a Mg${\mathrm{F}}_{2}$ semicylinder onto thin (\ensuremath{\sim} 200-\AA{}) films of Al. Photon energies from threshold at 4.8 up to 10.2 eV were used. For $p$-polarized light near threshold, a surface-plasmon resonance peak…
Strontium atoms were reacted with N2O, O3, O2, NO, Br2, Cl2, and F2 in a flow system to produce the diatomic oxide or halide. Photon yields were measured from these reactions in a bath of argon at pressures of 1.1–9.5 Torr. Photon yields in excess of 6×10−2 for the SrO A 1Σ–X 1Σ band system were observed with both N2O…
The effects of the zero-point energy, residual forces and torques on the molecules, and molar density, on the calculated lattice frequencies and structural properties of solid α- and γ-N2, are investigated. An intramolecular potential and a parametrized 12-6 atom–atom intermolecular potential are used to calculate lat…
A polarizable point-ion shell model has been developed for $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$. The material is treated as perfectly ionic, the repulsive interactions were calculated from free-ion wave functions, and the single empirical parameter of the model was obtained from an anal…
Some properties of a linear chain of harmonically coupled double wells are studied by the technique of the transfer operator. Exact values for the chain specific heat, the displacement probability density, and the first six even moments of the dynamical displacement correlation function are obtained. The model is show…
A 75-keV electron beam with a low angular divergence (8 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}6}$ rad) combined with a Wien filter spectrometer is used to measure the dispersion of the ${\ensuremath{\omega}}^{+}$ and ${\ensuremath{\omega}}^{\ensuremath{-}}$ modes for suface plasmons in thin oxidized…
A theory of the vibrational spectra of glasses is presented, and equations are derived specifically for the Raman intensities. The theory is applicable to glasses of the oxide type [such as glasses in the system ${M}_{2}\mathrm{O}\ensuremath{-}L \mathrm{O}\ensuremath{-}\mathrm{S}\mathrm{i}{\mathrm{O}}_{2}\ensuremath{-…
The first measurement of the hole mobility and its temperature dependence in thermally grown SiO2 on Si is reported and found to follow μ≃20 exp(−0.6eV/kT) cm2/V sec. In agreement with previous studies, the energy required to form an electron−hole pair with ionizing radiation is found to be field dependent and at very…
The classical Mie theory for the scattering and absorption of electromagnetic radiation by a sphere is extended so as to be applicable to cases in which longitudinal polarization waves can propagate in the sphere material. The extended Mie theory is applied to the calculation of the optical properties of small metal s…
The lineshape is studied in the simplest approximation free from the difficulty of divergence caused by a singular nature of the system. Characteristics of the linewidth are obtained for both short- and long-ranged scatterers. By assuming δ-potential scatterers, the lineshape is calculated explicitly as a function of…
The electronic-energy-band structure and full-Brillouin-zone Fermi surfaces of the layered dichalcogenides, $1T\ensuremath{-}\mathrm{T}\mathrm{a}{\mathrm{S}}_{2}$ and $1T\ensuremath{-}\mathrm{T}\mathrm{a}{\mathrm{Se}}_{2}$, have been calculated using the Korringa-Kohn-Rostoker method in the muffin-tin approximation. W…
It is pointed out that a model which agrees well with the observed properties of semiconducting glasses is an attractive Hubbard model of localized states. Such a model has no gap for two-electron excitations but an energy gap for one-electron ones. The suggested physical model for a two-electron excitation is a new c…
Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase change from a tetragonal to an orthorhombic form at 160K is a first-order transition. A transverse acoustic phonon mode, which has the symmetry of the phase change, was observed at very low energies and showed 'softenin…