Materials Literature
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The real-space dynamics in a model system of colloidal hard spheres was studied by means of time-resolved fluorescence confocal scanning microscopy. Direct experimental evidence for the presence of dynamical heterogeneities in a dense liquid was obtained from an analysis of particle trajectories in two-dimensional sli…
The polarizabilities of Si clusters with 9 to 28 atoms are calculated using a density functional cluster method. The atomic geometries are based on those carefully optimized by energy minimization. The polarizability shows fairly irregular variation with cluster size, but all calculated values are higher than the pola…
We investigate the scaling properties of the Barkhausen effect, recording the noise in several soft ferromagnetic materials: polycrystals with different grain sizes and amorphous alloys. We measure the Barkhausen avalanche distributions and determine the scaling exponents. In the limit of vanishing external field rate…
We report calculations of high electric field transport for the case of a strained Si/GeSi double heterostructure (DHS) considering transport along the Si channel and by applying the analytical Fokker-Planck approach (FPA), where the process is modeled as drift-diffusion in energy space. We limit ourselves to electron…
Experimental search for molecular-nuclear transitions H_2O\to^{18}Ne^*(4.522,1^-)\to^{18}F\to^{18}O in water molecules was carried out. The measurements were performed in a low-background laboratory at the Baksan Neutrino Observatory. Under the assumption that the above transitions take place, the estimate for the hal…
The cubic lattice symmetry of ferromagnetic homogeneously disordered alloys is when a compositional modulation is imposed. This can have a profound influence on the magnetocrystalline anisotropy energy (MAE). We describe our ab-initio theory of this effect and use the framework of concentration waves with the electron…
In discrete energy structure of nanoscale magnets, nonadiabatic transitions at avoided level crossings lead to fundamental processes of dynamics of magnetizations. The thermal environment causes dissipative effects on these processes. In this paper we review the features of the nonadiabatic transition and the influenc…
Sheared concentrated colloids with short range polymer coats are examined via simulations. Distributions of force are found to be sums of exponentials. The 'hydrodynamic clustering' underlying the shear thickening effect is shown, in this system, to be a network of percolating coat contacts, with coats both in compres…
[reaction: see text] The reaction pathway for peroxide-initiated aldehyde-mediated oxidation of olefins to epoxides by molecular oxygen has been studied. The pathways of reaction via a peroxy acid or an acyl peroxy radical have been differentiated by investigation of the reaction of 4 with oxygen to provide 6 via 8.
Delta 5-3-ketosteroid isomerase (KSI) catalyzes the allylic isomerization of Delta 5-3-ketosteroids at a rate approaching the diffusion limit by an intramolecular transfer of a proton. Despite the extensive studies on the catalytic mechanism, it still remains controversial whether the catalytic residue Asp-99 donates…
The hexamolybdopyrophosphate [(O3POPO3)Mo6O18(H2O)4]4- (1) has been characterized by 31P NMR, IR, elemental analysis, and single-crystal X-ray diffraction. This polyoxoanion consists of a six-membered ring of MoO6 octahedra, which alternate in sharing edges and corners. The (O3POPO3)4- anion is bound with P(1) in the…
The novel, dimeric polyoxometalate [{(P2O7)Mo15O45}2]8- has been characterized by 31P NMR spectroscopy and single-crystal X-ray diffraction. The 30-molybdobispyrophosphate contains two eclipsed diphosphate ions with linear P−O−P bonds (180.0(10)°). The polyanion can be viewed as a fused dimer of two lacunary [(P2O7)Mo…
CVD studies devoted to platinum and palladium deposition on planar substrates for microelectronics have clearly shown that it is possible to reach high-quality deposits at temperatures above 200 °C. Attempts to prepare pure metallic deposits at temperatures around 100 °C and even lower are of general interest, since a…
A series of disklike compounds containing the pyrazabole ring have been prepared by reaction of 3,5-diarylpyrazoles and borane. The aryl groups are benzene rings substituted with one, two, or three hexyloxy, decyloxy, or tetradecyloxy groups. The study of the liquid crystalline properties shows that the optimal chain…
Thin stacks consisting of a single intrinsic Josephson junction on (Bi,Pb)-Sr-Ca-Cu-O thin films are investigated under the influence of external microwave fields. The $I$-$V$-characteristic shows a single resistive branch, a clear superconducting gap edge structure and a pronounced current step in external microwave…
A microscopic theory for the coupling of intrinsic Josephson oscillations and dispersive phonon branches in layered superconductors is developed. Thereby the effect of phonons on the electronic c-axis transport enters through an effective longitudinal dielectric function. This coupling provides an explanation of recen…
We derive a formula, useful for first-principles calculations, which relates the free energy of an oxide/metal interface to the free energies of surfaces and the work of separation of the interface. We distinguish the latter {\it mechanical} quantity from the {\it thermodynamic} work of adhesion, and we describe expli…
A review of the approximations in any time-dependent density functional calculation of excitation energies is given. The single-pole approximation for the susceptibility is used to understand errors in popular approximations for the exchange-correlation kernel. A new hybrid of exact exchange and adiabatic local densit…
In seeking to understand at a microscopic level the response of dislocations to stress we have undertaken to study as completely as possible the simplest case: a single dislocation in a two dimensional crystal. The intention is that results from this study will be used as input parameters in larger length scale simula…
The role of the exchange-correlation potential and the exchange-correlation kernel in the calculation of excitation energues from time-dependent density functional theory is studied. Excitation energies of the He and Be atoms are calculated, both from the exact ground-state Kohn-Sham potential, and from two orbital-de…