Materials Literature
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A new efficient numerical algorithm for interacting fermion systems is proposed and examined in detail. The ground state is expressed approximately by a linear combination of numerically chosen basis states in a truncated Hilbert space. Two procedures lead to a better approximation. The first is a numerical renormaliz…
In the Brazil nut problem (BNP), hard spheres with larger diameters rise to the top. There are various explanations (percolation, reorganization, convection), but a broad understanding or control of this effect is by no means achieved. A theory is presented for the crossover from BNP to the reverse Brazil nut problem…
The low-lying electronic transitions in a peroxy radical, ≡Si–O–O•, a fundamental radiation induced point defect in silicon dioxide, have been investigated by means of ab initio multiconfiguration perturbation theory calculations, CASPT2, and cluster models. The accuracy of the computed transition energies and intensi…
The dynamical behavior of a thin film of ice Ih deposited on MgO(001) surface has been investigated both experimentally and theoretically. Incoherent neutron quasielastic scattering experiments, using uniform MgO powders, show that a quasiliquid water layer of monolayer thickness exists at T=265 K. The translational m…
In this work we introduce two models to understand the anomalous composition dependence of viscosity of binary mixtures. Both models consist of a mixture of two molecular species (A and B) with the same diameter and mass but varying solute–solvent Lennard-Jones interaction. In model I, the two different species are st…
The behavior of the various relaxation modes in poly(ε-caprolactone) (PCL), is studied by Broad Band Dielectric Spectroscopy in the frequency range from 3×10−3 to 1.8×109 Hz and from 133 to 313 K. The experimental trace of the dielectric loss as a function of the angular frequency, ε″(ω), is analyzed by best fitting a…
The catalytic reaction between adsorbed oxygen atoms and CO molecules on Pt(111) was investigated by scanning tunneling microscopy and modeled by Monte Carlo simulations. Experiments were performed by dosing preadsorbed Oad layers with CO between 237 and 274 K. Two stages were observed during dosing with CO, an initia…
The mononuclear gadolinium mixed-ligand complex [Gd(CF3CO2)3(phen)2(H2O)] has been prepared and structurally characterized by X-ray crystallography. Two complex molecules are doubly bridged by H bonds between carboxylate and aqua ligands with a Gd−Gd separation of 7.16(1) Å. Magnetic susceptibility and EPR measurement…
Isolation of the free bicyclic tetraamine, [3(5)]adamanzane.H(2)O (1,5,9,13-tetraazabicyclo[7.7.3]nonadecane.H(2)O), is reported along with the synthesis and characterization of a copper(II) complex of the smaller macrocycle [(2.3)(2).2(1)]adamanzane (1,5,9,12-tetraazabicyclo[7.5.2]hexadecane) and of three cobalt(II),…
Surface bound chitosan−sialodendrimers with a high degree of substitution were successfully prepared using a doubly convergent approach. Poly(amidoamine) (PAMAM) dendrimers ( G = 1−5) having a 1,4-diaminobutane core were amidated to N -carboxyethylchitosan methyl ester under conditions that prevented cross-linking. Th…
The first photosensitive liquid crystalline (LC) dendrimer with terminal cinnamoyl groups was synthesized. A new approach to the synthesis of photochromic carbosilane LC dendrimers was elaborated. The method consists of synthesis of dendrimer with terminal hydroxyl groups and then coupling of 4-methoxycinnamoyl chlori…
Unionid shells are characterized by an outer aragonitic prismatic layer and an inner nacreous layer. The prisms of the outer shell layer are composed of single-crystal fibres radiating from spheruliths. During prism development, fibres progressively recline to the growth front. There is competition between prisms, lea…
Simulations have been performed at 473 K for one-component melts of polyethylene (PE) and head-to-head, tail-to-tail polypropylene (hhPP) as well as a mixture of the two species. The densities are 0.760, 0.753, and 0.756 g/cm 3 for these three NVT simulations, respectively. The Monte Carlo simulation uses coarse-grain…
The 23 Na and 29 Si NMR spectra of the sodium−silicon clathrate materials Na 8 Si 46 and Na x Si 136 (1 < x < 24) and the parent Zintl phase NaSi have been studied in detail with a view to ironing out a number of ambiguities in the published literature and to determining properties of these potential thermoelectric ma…
Copper(II) azide complexes of three tridentate ligands namely 2,6-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L), 2,6-(pyrazol-1-ylmethyl)pyridine (L'), and dipropylenetriamine (dpt) yield three kinds of complexes with different azide-binding modes. The ligand L forms two end-on-end (mu-1,3) diazido-bridged binuclear co…
A theoretical and computational study of the nitrogen superhyperfine structure in Cu(II) complexes is reported. The determination of hybridization parameters for nitrogen donor orbitals from the data is examined. For most Cu(II) complexes the results deviate substantially from pure “sp 2 ” or “sp 3 ” hybridization. Se…
The combination of small-angle X-ray scattering and qualitative porosimetry is applied to the puzzling phenomenon of overly large specific surface areas in some mesoporous silicas. Geometrical calculations, considering the relationship between structure, lattice parameter, and specific surface area, reveal the latter…
The homoleptic complexes [Ph(4)P](2)[Co[N(CN)(2)](4)] and [Ph(4)P][M[N(CN)(2)](3)] [M = Co, Mn] have been structurally as well as magnetically characterized. The complexes containing [M[N(CN)(2)](4)](2-) form 1-D chains, which are bridged via a common dicyanamide ligand in [M[N(CN)(2)](3)](-) to form a 2-D structure.…
Manganese oxide catalysts supported on Al 2 O 3, ZrO 2, TiO 2, and SiO 2 supports were used to study the effect of support on ozone decomposition kinetics. In-situ laser Raman spectroscopy, temperature-programmed oxygen desorption, surface area measurements, and extended and near-edge X-ray absorption fine structure (…
The synthesis of silver and gold metal nanospherical particles stabilized by the fourth-generation poly(amido amine) (G4 PAMAM) dendrimer is reported. The reduction of silver nitrate and sodium tetrachloroaurate in the presence of the PAMAM dendrimer having terminal amine groups results in the formation of stable, wat…