Materials Literature
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The variety and complexity of the metal-insulator transitions that ${\mathrm{V}}_{2}$${\mathrm{O}}_{3}$ undergoes, in both pure form and when doped with other transition-metal ions, have resulted in widespread interest in the electronic structure of this oxide. We report here the results of a photoemission study of th…
It is shown theoretically that there is competition between core-hole decay and delocalization of a resonantly excited electron from the adsorbate to the substrate metal with simultaneous substrate-to-ligand charge-transfer core-hole screening [relaxation from the resonantly core excited neutral state to the x-ray-pho…
We used scanning tunneling microscopy and low-energy electron microscopy to study the etching of the Si(100)-(2\ifmmode\times\else\texttimes\fi{}1) surface by oxygen at low pressures and elevated temperatures. At 5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$ torr partial pressure of oxygen, the…
Barium titanate (BaTiO3) thin films grown by the metalorganic chemical vapor deposition (MOCVD) technique on MgO substrates have been investigated by second-harmonic generation at an incident wavelength of 1.064 μm. Transmission electron microscopy was used to show that substrate quality and pretreatment (annealing) h…
The asymmetric unit of [(CH 3 ) 3 CNH 3 ] 6 [Mo 7 O 24 ].7H 2 O consists of a heptamolybdate anion, six tert-butylammonium cations and seven water molecules. The crystal packing is stabilized by electrostatic interactions and an extensive network of hydrogen contacts involving the O atoms from the polyanion, the water…
Cadmium selenite has two polymorphic forms: CdSeO 3 (oP20) and CdSeO 3 (mP40). In the orthorhombic form the coordination polyhedron around cadmium is an octahedron and in the monoclinic form it is a trigonal prism. In 4CdSeO 3 .3H 2 O the coordination polyhedra are distorted between octahedra and trigonal prisms
The yttrium(III) and lanthanum(III) complexes of 9,14-dioxo-1,4,7,10,13-pentaaza-1,4,7-cyclopentadecanetriacetic acid, namely, diaquabis(9,14-dioxo-O 14 :O 9 -1,4,7,10,13-pentaaza-N 1 ,N 4 :N 7 -1,4,7-cyclopentadecanetriacetato-O 1 ,O 4 :O 7 )diyttrium(III) tetradecahydrate [Y 2 (C 16 H 24 N 5 O 8 ) 2 (H 2 O) 2 ].14H…
A distinct positive temperature coefficient of resistivity (PTCR) effect has been observed in undoped barium titanate ceramics sintered in the temperature range 1300–1400 °C in air. Although undoped barium titanate is normally insulating and ferroelectric at room temperature, it has been found that semiconducting bari…
Abstract The molecular organization of polymer melts and glasses remains a challenging area of polymer physics. Recent advances in simulation procedures and quantitative atomistic based X-ray and neutron scattering studies have shown most conclusively that the historical view of some level of local parallelism between…
We develop the hybrid Monte Carlo method for simulations of single off-lattice polymer chains. We discuss implementation and choice of simulation parameters in some detail. The performance of the algorithm is tested on models for homopolymers with short- or long-range self-repulsion, using chains with 16≤N≤512 monomer…
Abstract A new type of membrane polymer, containing a photosensitive moiety, was synthesized. The photochemically induced functionalization and crosslinking of poly [acrylonitrile‐co‐butadiene‐co‐styrene‐co‐2‐(4‐ethenyl) phenyl‐5‐phenyl‐2H‐tetrazole], ABSV, has been studied. A variety of dipolarophiles and phenolic co…
Modulated-beam mass spectrometry and x-ray photoelectron spectroscopy (XPS) have been used to investigate the interaction of CH4, C2H4, C5H10, and H2 with carburized and uncarburized tungsten. It is shown that significant evaporation of C1, C2, and C3 occurs for carburized tungsten at temperatures above 1900 °C. The t…
This work presents the anisotropic pseudorotation (APR) model, which is a new dynamic model for the interpretation of experimental nuclear spin-lattice relaxation times in paramagnetic (S=1) complexes of low symmetry. It comprises two dynamic processes active in modulating the zero-field splitting interaction (ZFS). R…
Noble gas (He,Ar,Xe) and reactive gas (O2,N2) plasma treatments of polymethylmethacrylate (PMMA) and polyethyleneterephthalate (PET) surfaces were performed in an electron-cyclotron-resonance plasma. In situ surface analysis by x-ray photoelectron spectroscopy reveals well-defined surface compositions. From these meas…
Abstract Microphase separation in block copolymer systems forms well-defined, periodic structure on the sub-micron length scale. This structure arises from the system striving to satisfy the delicate balance of minimizing the area of contact between incompatible chain segments and maximizing the conformational entropy…
The resistance Rf of Pt and Ni films has been measured during deposition (by ion-beam sputtering) for different deposition rates r and substrate temperatures TS (300≤TS≤575 K). At the onset of deposition (the nucleation stage) Rf varies only slowly with deposition time T and oscillations occur in Rf vs T which are dam…
Abstract Significant advances in knowledge of lamellae and their organization in meltcrystallized polymers have stemmed from the ability to examine internal morphologies systematically with the transmission electron microscope. Spherulites form because the first-forming (dominant) lamellae branch repetitively, often a…
The electronic properties of amorphous carbon structures with varying microscopic mass densities, ranging from 2.0 to 3.52 g/${\mathrm{cm}}^{3}$, are analyzed. Using a semiempirical density-functional approach the model structures were generated by molecular dynamics performing a simulated cooling of liquid carbon clu…
The energetics and electronic structure of a series of neutral and charged oxygen and magnesium vacancy defects (F, ${\mathit{F}}^{+}$, ${\mathit{F}}^{2+}$, V, ${\mathit{V}}^{\mathrm{\ensuremath{-}}}$, ${\mathit{V}}^{2\mathrm{\ensuremath{-}}}$, and P centers) in MgO have been computed using the stationary total-energy…
Using a simple three-dimensional lattice copolymer model and Monte Carlo dynamics, we study the collapse and folding of proteinlike heteropolymers. The polymers are 27 monomers long and consist of two monomer types. Although these chains are too long for exhaustive enumeration of all conformations, it is possible to e…