Materials Literature
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Experiments determining the lifetime of excited electrons in crystalline copper reveal states which cannot be interpreted as Bloch states [S. Ogawa {\it et al.}, Phys. Rev. B {\bf 55}, 10869 (1997)]. In this article we propose a model which explains these states as transient excitonic states in metals. The physical ba…
Linear-scaling electronic-structure techniques, also called O(N) techniques, rely heavily on the multiplication of sparse matrices, where the sparsity arises from spatial cut-offs. In order to treat very large systems, the calculations must be run on parallel computers. We analyse the problem of parallelising the mult…
First-principles calculations are performed for electronic structures of two high pressure phases of solid selenium, $β$-Po and bcc. Our calculation reproduces well the pressure-induced phase transition from $β$-Po to bcc observed in selenium. The calculated transition pressure is 30 GPa lower than the observed one, b…
We present the theory of analytical Hartree-Fock gradients for periodic systems as implemented in the code CRYSTAL. We demonstrate how derivatives of the integrals can be computed with the McMurchie-Davidson algorithm. Highly accurate gradients with respect to nuclear coordinates are obtained for systems periodic in 0…
Poly(urethane-benzoxazine) films as novel polyurethane (PU)/phenolic resin composites were prepared by blending a benzoxazine monomer (Ba) and PU prepolymer that was synthesized from 2,4-tolylene diisocyanate (TDI) and polyethylene adipate polyol (MW ca. 1000) in 2 : 1 molar ratio. DSC of PU/Ba blend showed an exother…
Heat capacity of a quasi-one-dimensional organic conductor (DIMET) 2 I 3 has been measured by chopped-light ac calorimetry below room temperature. An anomaly due to a metal-insulator transition has been clearly detected around 40 K. The magnitude of the anomaly is analyzed through comparison with other Q1D conductors.…
The electronic and magnetic properties of double-layered Roddlesdon-Popper compounds, ${\mathrm{La}}_{1+2x}{\mathrm{Sr}}_{2\ensuremath{-}2x}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ with different doping x from 0.0 to 0.2 have been calculated using the full-potential linear muffin-tin orbital method. The total energies, band…
3,8-Diaryldifurano[2,3-a:2',3'-f]naphthalenes were prepared in two simple steps. First, 1,5-dihydroxynaphthalene and 1-aryl-2-bromodecan-1-ones were condensed to the corresponding naphthalene 1,5-diethers. Second, these intermediates were cyclized using methanesulfonic acid in methylene chloride. Seven examples are gi…
Systematic Raman scattering investigations were carried out on TPP during the isothermal transformations of the supercooled liquid into the glacial state, in the 210−230 K temperature range. From these experiments the glaciation process can be interpreted in terms of aborted crystallization. This study reveals that th…
New chelate complexes of copper diiminate and iron diiminate were synthesized. Their physical characteristics have been studied. The diffusion of supercritical carbon dioxide (scCO 2 ) into polyarylate (PAR) films and their impregnation with diiminates were investigated. The equilibrium degree of PAR swelling in scCO…
We report the formation of highly organized fibrous networks on ∼50 nm thick oligomeric films of hydrolyzed γ-(aminopropyl)triethoxysilane (γ-APS) adsorbed on Na + -containing substrates. The growth of these nanostructures is dependent on the surface segregation of Na + ions and exposure to ambient conditions. Using a…
The stability of surface structure and space-charge distribution in free TiO2 nanoparticles are investigated for both rutile and anatase phases using a variable-charge interaction potential in which atomic charges vary dynamically depending on their environment. We find the dynamic charge transfer: (i) enhances atomic…
The density-of-states (DOS) near Fermi level of a single-wall carbon nanotube is studied in the presence of a magnetic field (B) parallel to the nanotube axis. Expressions of the band gap and the DOS near the Fermi level are derived in the case of with and without spin-$B$ interaction. A magnetic-field-induced metal-i…
We have studied the hole levels and exciton states in CdS nanocrystals by using the hole effective-mass Hamiltonian for wurtzite structure. It is found that the optically passive ${P}_{x}$ state will become the ground hole state for small CdS quantum dots of radius less than 69 \AA{}. It suggests that the ``dark excit…
Molecular design of a novel dendrimer porphyrin for supramolecular fullerene/dendrimer hybridization, Molecular design of a novel dendrimer porphyrin for supramolecular fullerene/dendrimer hybridization
A three-dimensional structure comparison between the dimeric regulatory serine-binding domain of Escherichia coli D-3-phosphoglycerate dehydrogenase [Schuller, D. J., Grant, G. A., and Banaszak, L. J. (1995) Nat. Struct. Biol. 2, 69-76] and the regulatory domain of E. coli threonine deaminase [Gallagher, D. T., Gillil…
The crystal structure and magnetoresistance of the polycrystalline La1−xLixMnO3 (x=0.10, 0.15, 0.20, 0.30) are investigated. The result of the Rietveld refinement of x-ray powder diffraction shows that the room temperature structural transition from rhombohedral (R3̄C) to orthorhombic (Pbnm) symmetry occurs at the Li-…
Field emission characteristics of various kinds of single-wall carbon nanotubes have been calculated using a combination of methods derived from quantum and electromagnetic theory. The energy distributions of the emitted electrons, obtained for all the nanotubes, confirm the implication of localized states in the emis…
Resonance Raman scattering from 1 and 2 LO phonons is investigated from Cd1−xZnxS nanoparticles dispersed in oxide glass before and after annealing. The resonance profiles are found to exhibit asymmetry which is attributed to the interference effects arising from a nonresonant contribution to the polarizability. The e…
Based on optical fundamentals, we present in this article a practical method to obtain an interference fringe-free transmission spectrum for hydrogenated amorphous solid thin films. From this spectrum, reliable optical properties, such as the Urbach edge and optical band gap of the thin films, can be extrapolated dire…