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Total energy pseudopotential calculations of missing dimer reconstructions on the Si(001) surface are presented. The authors have calculated the energy of the ideal unreconstructed surface and the energy of the (2*1) symmetric dimer, the (2*4) single missing dimer, the (2*2) single missing dimer and the (2*4) double m…
Valence band and core-level characteristics of sputter-deposited Fe–Cu, Fe–Ag and Fe–Cu–Ag alloy films have been studied by X-ray photoelectron spectroscopy using monochromatized Al Kα radiation. These films are composed of metastable bcc, fcc and amorphous phases depending on the alloy composition. Their valence band…
Optical absorptions in the tail region and the reflectivity at room temperature in the VUV region up to ∼40 eV are measured for YAG single crystals. Various optical constants are derived therefrom as functions of photon energy by means of the Kramers-Kronig relation. The Urbach rule parameters are determined experimen…
Hall mobility of photoexcited holes in the \(\varGamma_{7}^{+}\) valence band of Cu 2 O has been measured at low temperatures. On the basis of the theory of carrier-lattice interactions in polyatomic crystals the intrinsic scattering mechanisms of this substance have been clarified, for the first time, in a wide tempe…
We study the center model of Penrose lattices with a fivefold rotational symmetric axis in the framework of a tight-binding Hamiltonian. The inflation (or production) rules of ``finite Penrose patterns'' generated by repeated application of deflation and rescaling are found, which show a definite hierarchical structur…
Selectively excited emission and ${\mathrm{Tb}}^{3+}$\ensuremath{\rightarrow}${\mathrm{Ce}}^{3+}$ energy transfer in ${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$:Tb,Ce (YAG:Tb,Ce) at room temperature were studied. The selective excitation included a 266.0-nm laser pulse. The processes of ${\mathrm{Tb}}^{3+…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTArrhenius parameters for solid-state reactions from isothermal rate-time curvesMichael E. Brown and Andrew K. GalweyCite this: Anal. Chem. 1989, 61, 10, 1136–1139Publication Date (Print):May 15, 1989Publication History Published online1 May 2002Published inissue 15 May 1989h…
Infrared and visible absorption spectra have been measured on three kinds of mixed-stack organic charge-transfer crystals of tetrathiafulvalene (TTF) -p-benzoquinone derivatives under hydrostatic pressures up to about 50 kbar. In TTF-tetrachloro-p-benzoquinone and TTF-trichloro-p-benzoquinone crystals, the regularly s…
It is shown how to extend Feibelman's framework [Prog. Surf. Sci. 12, 287 (1982)] for the reflectivity of a jellium surface to a more general situation, by expressing his matching conditions and their generalization in terms of macroscopic boundary conditions. A generalization of his reflectivity formulas to a nonjell…
The x-ray-absorption spectra of ${\mathrm{Ag}}_{2}$O are reported. Good agreement is obtained with a band-structure calculation using the atomic-sphere approximation with an extended basis set. The observation of the white line is an indication of the nonclosed 4d shell of Ag in this compound, although the exciton con…
The results of spectroscopy and transient-photoconductivity measurements are presented for polyaniline in the fully reduced form (leucoemeraldine) and in the emeraldine-base form. Results from partially crystalline films (cast from solution in sulfuric acid) and from amorphous films (cast from dimethylforamide) are co…
The B12 icosahedron, hitherto assumed to be regular, is actually distorted by the Jahn-Teller effect. Accordingly the degeneracy of the uppermost partially occupied energy level is lifted, and occupied and unoccupied states become separated. Hence in most boron-rich solids with icosahedral structures an intrinsic high…
An optical study of the excitonic Mott transition in GaSe at liquid-He temperature is presented. In recording the optical spectra, care was taken to reduce the effects of the spatial inhomogeneity of the photoexcited carriers as much as possible. The transition we observed is smooth and continuous. We discuss the cont…
X-ray diffraction data for crystalline and molten polyethylene are analyzed to yield radial distribution functions. Use of scattering factors for CH2 groups in the data reduction yields unambiguous, model-independent information on the relative positions of carbon atoms. Direct comparison of the atom pair distribution…
The refractive index, optical nonlinearity, and other related parameters of some mixed-defect compounds for the first time have been evaluated using the bond-charge model of Levine and the approach of Samanta et al. and the results are compared with available experimental values. We have further discussed the device f…
Large oscillator strengths are predicted for optical transitions between conduction subbands of Si-Si0.5 Ge0.5 strained-layer superlattices. The transition energies in question are in the infrared range (50–300 meV).
A new Monte Carlo calculation model is presented to simulate not only the primary electron behavior but also the secondary electron cascade in a specimen bombarded with an electron beam. Electrons having energy greater than 0.1 keV are treated as ‘‘fast electrons’’ and the previous single scattering Monte Carlo model…
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We present evidence for the existence of defect states with large mass and low mobility in the conducting polymer polyaniline. This large-energy-gap polymer has been shown to have properties significantly different from many other conducting polymers. Photoinduced infrared absorption studies presented here are consist…
A stable and reproducible negative-resistance effect has been observed in various mixed-stack organic charge-transfer crystals having ionicities close to the neutral-ionic phase boundary. Systematic studies on several kinds of single crystals indicate that this effect is an intrinsic property, arising from the dynamic…