Materials Literature
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Theoretical calculations of electron energy-loss near-edge structure (ELNES) and x-ray absorption near-edge structure (XANES) of selected wide-gap materials including ${\text{TiO}}_{2}$, AlN, GaN, InN, ZnO, and their polymorphs are performed using a first-principles method. Calculations of 39 $K$ and ${L}_{3}({L}_{2,3…
Polyelectrolyte multilayers with alternating porous and fully dense regions have been assembled from poly(acrylic acid) (PAA), poly(allylamine hydrochloride) (PAH), and poly(sodium 4-styrenesulfonate) (SPS) in appropriate combinations. The porous zones were developed postassembly via immersion of the heterostructure f…
A self-consistent electronic structure calculation based on the Luttinger-Kohn model is performed on GaMnAs/GaAs multilayers. The Diluted Magnetic Semiconductor layers are assumed to be metallic and ferromagnetic. The high Mn concentration (considered as 5% in our calculation) makes it possible to assume the density o…
We present a new linear scaling method for the energy minimization step of semiempirical and first-principles Hartree-Fock and Kohn-Sham calculations. It is based on the self-consistent calculation of the optimum localized orbitals of any localization method of choice and on the use of orbital-specific basis sets. The…
A novel class of mesoporous aluminosilicate molecular sieves has been prepared by replication from carbon mesoporous molecular sieves (CMKs) using zeolite precursors and characterized by a variety of analytical and spectroscopic techniques, such as XRD, N 2 adsorption/desorption, SEM/TEM, IR, hyperpolarized (HP) 129 X…
It was hypothesized that nanoscale adhesion ligand spacing regulates cell adhesion, proliferation, and differentiation, and that this control can be decoupled from the overall ligand density. Alginate was chemically modified with a peptide containing the cell adhesion sequence arginine−glycine−aspartic acid (RGD), and…
We apply standard, first-principles calculations to a complete treatment of lattice dynamics in the harmonic approximation. The algorithm makes use of the straightforward ``frozen-phonon'' approach to the calculation of vibrational spectra and addresses some limitations of the method. Our prescription's validity is in…
We study the role of strong electron confinement in surface-enhanced Raman scattering from molecules adsorbed on small noble-metal particles. We describe a new source of Raman signal enhancement which originates from different behavior of sp-band and d-band electron densities near the particle boundary. In small parti…
We report the results of an x-ray scattering study that reveals oxidation kinetics and formation of a previously unreported crystalline phase of SnO at the liquid-vapour interface of Sn. Our experiments reveal that the pure liquid Sn surface does not react with molecular oxygen below an activation pressure of \~5.0*10…
We study inverted core/shell nanocrystals (NCs) in which a core of a wide gap semiconductor (ZnSe) is overcoated with a shell of a semiconductor of a narrower gap (CdSe). By monitoring radiative recombination lifetimes for a series of these NCs with a fixed core radius and progressively increasing shell thickness, we…
The structure and dynamics of poly(amido amide) (PAMAM) dendrimers have been of great interest both scientifically and industrially, but such important features as the distributions of atoms, channels, and strain inside these molecules remain unresolved. This paper reports results from systematic investigations of the…
Die komplexe Molekülstruktur des ionischen Clusters [Ag26In18S36Cl6(dppm)10(thf)4]2+[InCl4(thf)−]2 (siehe Bild) wurde sowohl mithilfe theoretischer Methoden (Dichtefunktionaltheorie) als auch experimentell (Einkristallröntgenbeugung, FT-Massenspektrometrie) bestimmt. Der Cluster entstand bei der Umsetzung von AgOOCPh…
Abstract We have prepared four new octaaminoamide resorcin[4]arenes having hydrocarbon chains of different lengths ( 1 , 2 : R = CH 3 ; 3 , 4 : R = C 11 H 23 ) and different terminal groups ( 1 , 3 : NH 2 ; 2 , 4 : NMe 2 ). The surface tension and self‐assembly of aqueous solutions of 2 − 4 were studied and their crit…
Abstract Summary: In a series of papers the crystallization of a commercial polyethylene (PE) material has been studied by in situ ultra small‐angle X‐ray scattering (USAXS) and it has been found that the placement of crystallites is predominantly a random car parking process, dealt with in the field of random sequent…
Abstract Dispersed calcium carbonate particles are encapsulated with poly(methyl methacrylate). The optimum condition for the polymerization is investigated; and the encapsulated particles are characterized by spectrophotometric analysis, acid decomposition, thermal analysis, and microscopic observation. From the conv…
Abstract Methyl anacardate and secondary butyl anacardate were prepared from anacardic acid and corresponding alcohols and were used, in addition to cardanol, as blocking agents for 2,4‐toluene diisocyanate (TDI). Blocked diisocyanate adducts were characterized via nitrogen estimation, Fourier transform infrared spect…
Using a density functional approach, we study the structural and magnetic properties of the pyrox\penalty1000\-\allowhyphens{}ene compound ${\mathrm{N}\mathrm{a}\mathrm{T}\mathrm{i}\mathrm{S}\mathrm{i}}_{2}{\mathrm{O}}_{6}$. While all previous workers are taking that ${\mathrm{N}\mathrm{a}\mathrm{T}\mathrm{i}\mathrm{S…
Electron-deficient silicon atoms, which are generated on a silica surface by evacuation above 900 K, are attacked by Grignard reagents (see picture). This reactivity provides a novel route for the surface modification of mesoporous silicas as the organic groups are strongly bound to the surface through the formation o…
We study the effects of oversized solute atoms on the diffusion of clusters of self–interstitial atoms produced in metals by high–energy irradiation. We use kinetic Monte Carlo (KMC) simulations in model body–centred cubic iron, and include elastic interactions between the defects. We show that elastic repulsion betwe…
We report the results of the first-principles calculation on the atomic displacement parameters, the crystal structure factors, and the charge density distributions of $\mathrm{Mg}{\mathrm{H}}_{2}$ at finite temperature. Our calculations have been performed with the ultrasoft pseudopotential method and the linear resp…