Materials Literature
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We present converged first-principles calculations for the atomic and electronic structure of diamond (111) surfaces based on density-functional theory in the local-density approximation. Single- and triple-dangling- bond surfaces with 1\ifmmode\times\else\texttimes\fi{}1, 2\ifmmode\times\else\texttimes\fi{}1, and ($\…
Stable platinum oxide films have been prepared through magnetron sputtering and have been analyzed on the bases of energy-sensitive microanalyses, x-ray diffraction, resistivity, and optical reflectance measurements. The complex dielectric function has been determined for various oxygen contents in the film covering t…
Effect of curvature-induced strain on the covalent bonding in isolated and selected single-shell and multi- shell carbon nanotubes is explored, using electron energy-loss spectroscopy (EELS) on the core K level, which probes the distribution of available unoccupied states in the conduction band. Results show that the…
We have studied luminescence properties of nanometer-sized Si crystallites fabricated by laser breakdown of ${\mathrm{SiH}}_{4}$ gas. An exponential absorption tail is observed and red photoluminescence (PL) appears in the exponential tail. The PL decay behavior is characterized by a stretched exponential function. At…
Quantum-beat spectroscopy has been used to observe excited states of the N-V center in diamond. For the 1.945-eV optical transition, direct evidence is presented for the existence of GHz-scale fine structure, together with a much larger 46-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ level splitting in the E state. An i…
The orbital and spin orderings of ${\mathit{d}}^{2}$ Jahn-Teller systems are studied in the generalized gradient approximation (GGA) by using the full-potential linearized augmented-plane-wave method. For the low temperature distorted crystal structures in ${\mathrm{YVO}}_{3}$ and ${\mathrm{LaVO}}_{3}$ perovskites, we…
We introduce a novel polarizing beam splitter that uses the anisotropic spectral reflectivity (ASR) characteristic of a high-spatial-frequency multilayer binary grating. Such ASR effects allow us to design an optical element that is transparent for TM polarization and reflective for TE polarization. For normally incid…
Two-photon excitation spectra of highly monodisperse colloidal CdSe nanocrystals with sizes ranging from 22 to 43 \AA{} are compared to one-photon excitation data and to a spherically confined effective-mass model. The main experimental features are well described by this model. However, the first one-photon and two-p…
Melts of semiflexible AB diblock copolymers are studied using the wormlike chain model and self-consistent-field theory. The diblocks considered here are symmetric in composition and in A- and B-block flexibility. Under these conditions, the microstructure formed is lamellar. We find that an increase in molecular rigi…
In this work we present a theoretical justification, based on a two-state model, of the recently observed close resemblance between the molecular first-order hyperpolarizability (${\mathrm{\ensuremath{\beta}}}^{\mathit{e}}$) obtained with traditional experimental or theoretical methods and the vibrational (or relaxati…
A method which takes into account normalized oscillator strengths is detailed for the calculation of parameters in Judd–Ofelt theory (B. R. Judd, Phys. Rev. 127, 750 (1962), G. S. Ofelt, J. Chem. Phys. 37, 511 (1962)). In the case of a Pr3+-doped fluorozirconate glass, the Judd–Ofelt parameters obtained in this way do…
Epitaxial growth in a CdS/HgS heterostructure of nanometer dimensions, prepared by methods of wet chemistry, is demonstrated. High-resolution transmission-electron microscopy is used to determine the shape and crystallinity of this system consisting of a quantum well in a quantum dot. The homogeneous absorption and fl…
Planarization of large grain diamond films has been induced by 193 nm excimer laser irradiation. Secondary emission images and cathodoluminescence (CL) in the scanning electron microscope have been used to characterize the irradiated area. Irradiation causes changes in the structure of defects involving nitrogen and v…
Optical absorption spectra were measured around the band edge in ( CH 3 NH 3 ) 3 Bi 2 I 9 single crystals. In the very thin crystals, an intrinsic exciton band appears clearly at 2.51 eV at low temperatures, and the absorption peak remains even at room temperature reflecting a large binding energy of more than 300 meV…
Ab initio calculations have been made of possible excited electronic structure of the N-V center in diamond. Molecular-orbital basis states for a center of ${\mathit{C}}_{3\mathit{v}}$ symmetry with n=2, 4, or 6 active electrons, which account fully for spin symmetries of the wave functions, were constructed to permit…
The resistivity, thermoelectric power (TEP), ESR and static susceptibility were measured on κ- and κ'- (BEDT-TTF) 2 Cu 2 (CN) 3 ; also, a band calculation based on an extended Hückel method was re-examined and the results were compared with those of related BEDT-TTF (ET) salts. Although the crystal- and calculated ban…
Carbon is well-known as an insulator, a semimetal, a molecular solid, and a one-dimensional semiconductor or low-density-of-states metal. We propose a pure-carbon planar structure composed of pentagons and heptagons that is metallic with a density of states at the Fermi level of \ensuremath{\sim}0.1 state per eV per a…
Collagen is most abundant in animal tissues as very long fibrils with a characteristic axial periodic structure. The fibrils provide the major biomechanical scaffold for cell attachment and anchorage of macromolecules, allowing the shape and form of tissues to be defined and maintained. How the fibrils are formed from…
We report the transient photovoltaic characters of a Schottky-type porous silicon diode excited by 10 ns laser pulses at 532 nm. At room temperature, the transient photovoltage profile consisted of two different decay components. The fast one had a characteristic decay time of 44 ns and the dominant slow process one o…
CASSCF/MRCI calculations have been performed for five states of ScCl , , , and for which values of the spectroscopic constants , , and are reported.