Materials Literature
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The electronic structure of the base forms of electrochemically prepared polyaniline is studied by means of x-ray photoelectron spectroscopy (XPS). Model compounds for the amine, imine and crosslinked nitrogen sites provide the references for the analysis of the core level spectra in the polymer. In particular, the an…
The possibility of whether BeO, a wide-band-gap semiconductor (7.8--10.7 eV), may exist in the layered graphitic phase---as do the other members of the family of first-row compounds C and BN---is investigated employing a first-principles total-energy local-density-approximation study of the electronic structure of thi…
Two compositions of BaTiO3 positive temperature coefficient of resistance ceramics, prepared identically except for the fact that a small addition of Mn (0.04 at. %) was made to one of them, were studied. The samples were sintered simultaneously in air at 1400 °C for 1 h and then annealed at 1200 ° for 5 h, using a mu…
An empirical embedded-atom potential for a bcc metal (vanadium) has been developed by fitting the embedding function, electron density, and pair interaction to the lattice constant, cohesive energy, elastic constants, and vacancy-formation energy. This potential has been used to calculate vacancy and divacancy propert…
Recently, attention has been focused upon laser plasma sources of thin-film diamond. These depend upon laser-ignited discharges in which intense pulsed currents flow through the small volume of carbon plasma ablated from graphite feedstock by a focused laser beam. The materials produced in this way generally resemble…
Dielectric properties of N(CH 3 ) 4 CdBr 3 single crystal have been studied. The dielectric constant along the c -direction shows a slight λ-type maximum at 156 K while that along the a -direction shows a discontinuity. The compound exhibits ferroelectric activity along the c -direction below the Curie temperature of…
Our previous paper [Phys. Rev. B 36, 1754 (1987)], in which Hosemann's paracrystal theory was extended to three-dimensional cubic systems, contained some errors. In this paper, we have corrected these errors and further refined the theory. The scattering profiles by our new theory are not so different from the previou…
Materials characterization for optical device purposes relies heavily on a knowledge of material compliances related to dielectric response. These include both linear response (dielectric constant) and various orders of nonlinear response involving electro-optics (Kerr and Pockels effects, harmonic generation, etc.) a…
Luminescence and optical absorption induced by an electron pulse and by a subsequent laser pulse have been studied in densified and undensified amorphous Si${\mathrm{O}}_{2}$ at 77 K. We find that the decay of the optical-absorption change induced by an electron pulse consists of two components: one which decays follo…
A bond-orbital theory of linear electronic response set out in the preceding companion paper (I) is expanded to include nonlinear response. Attention is focused on the third-order susceptibility ${\ensuremath{\chi}}_{\mathrm{ijkl}}^{(3)}$ (particularly as measured by the nonlinear refractive index ${n}_{2}$) in pretra…
The electronic structure of ${\mathrm{Ag}}_{2}$O has been investigated by photoelectron, Auger-electron, and bremsstrahlung isochromat spectroscopy. The experimental results are compared with model one-particle band-structure and two-particle cluster calculations. We extract values for the on-site Ag 4d and O 2p energ…
Diamond and diamondlike thin films produced by various chemical-vapor-deposition processes have been examined using Raman spectroscopy. These films exhibit features in the Raman spectra, suggesting that they are composites of crystalline and amorphous diamond and graphitic structures. The components of this composite…
The authors advance and examine a new mechanism which strongly influences the photoionisation processes above the 4d threshold in Xe and Ba. It is shown that the elastic and inelastic scattering of the inner-shell photoelectron by the outer-shell electrons determines the rate of single and double ionisation, decomposi…
In the authors' previous work data have been presented which indicate that thermoluminescence (TL) at 110 degrees C in crystalline quartz is due to the recombination of electrons released from (GeO 4 ) - centres with holes trapped at (AlO 4 ) 0 centres and at unidentified hole traps. In this paper new results are pres…
The antiferromagnetic structure of triclinic Cu 3 (PO 4 ) 2 (T N =22.2(5)K) has been determined at 2 K by unpolarised neutron diffraction from powdered and single-crystal samples prepared by hydrothermal synthesis. The triacute reduced chemical unit cell has a=4.855(1), b=5.288(1), c=6.184(1) AA, alpha =72.34(1), beta…
We demonstrate a fabrication process for making composite biological/solid-state heterostructures of nanometer dimension (nanoheterostructures). In this process individual protein molecules selectively self-assemble onto a 1.2-nm-thick Ta/W oxide film which has been patterned into a screen-like lattice with holes of 2…
The molecular dynamics with a first-principles interatomic potential is used to study the phase transition of quartz from the \ensuremath{\alpha} to \ensuremath{\beta} phase. The phase transition, successfully reproduced at about 850 K, is shown to have a peculiar dynamical character in that, although the probability…
The phonon structure of monolayer graphite formed on some transition-metal carbides has been investigated by using electron-energy-loss spectroscopy. The dispersion relations of the phonons in the monolayer graphite have indicated peculiar softening in intralayer chemical bonds and considerable bonding between the ove…
We report measurements of the valence- and core-level photoemission spectra of mass-selected, monodispersed Pt clusters. For individual samples consisting of the platinum atom through the six-atom cluster deposited onto a silica substrate, we have followed the development of the individual valence-band electronic stru…
Current issues and problems in the chemical vapor deposition (CVD) of diamond are those which relate to its characterization, its nucleation on foreign surfaces, the question of its formation in preference to the other phases of solid carbon (for example, graphite, chaoite, or lonsdaleite), why different morphologies…