Potentials generally used in molecular dynamics (MD) simulation of SiO2 properties customarily are calibrated to a combination of computed molecular electronic structure data and experimental crystalline data. The present study tests parametrization to data from high-level, first-principles electronic structure calculations alone. The issue is crucial to the success of multi-scale simulations. ...

The structures of the co-crystalline adducts of 3,5-di-nitro-benzoic acid (3,5-DNBA) with 4-amino-salicylic acid (PASA), the 1:1 partial hydrate, C7H4N2O6·C7H7NO3·0.2H2O, (I), and with 2-hy-droxy-3-(1H-indol-3-yl)propenoic acid (HIPA), the 1:1:1 d (6)-dimethyl sulfoxide solvate, C7H4N2O6·C11H9NO3·C2D6OS, (II), are reported. The crystal substructure of (I) comprises two centrosymmetric hydrogen-...

In this study a special type of silicoaluminophosphate with opal structure (Opal-SAPO) was prepared under microwave condition using tetraethylorthosilicate (TEOS), triethanolamine (TEA), aluminiumisopropoxid and phosphoric acid 85%. The product was characterized by X-ray diffraction (XRD), thermogravimetric (TGA) and Fourier Infrared Spectroscopy (FTIR).The crystalline product showed a good act...

The influence of the addition of carbon on the crystalline structure and resistivity of polycrystalline silicon layers grown by simultaneous decomposition of SiH,, C^H. a n d P H T a t '°"° c w a s studied. Carbon content, morphology, preferred orientation, crystallite size, lattice strains and resistivity were determined. It was found that carbon has a pronounced effect on the crystalline stru...

In the title compound, C(12)H(16)N(2)O(4)·H(2)O, the mol-ecular skeleton of the hydrazinecarboxyl-ate is nearly planar [within 0.053 (3) Å]. In the crystal, chains propagating along the c axis arise, composed of alternating hydrazinecarboxyl-ate mol-ecules and crystalline water, which inter-act via N-H⋯O and O-H⋯O hydrogen bonds.

An approach for description of the photoinduced nonlinear optical effects in the superconducting MgB₂:Cr₂O₃ nanocrystalline film is proposed. It includes the molecular dynamics step-by-step optimization of the two separate crystalline phases. The principal role for the photoinduced nonlinear optical properties plays nanointerface between the two phases. The first modified layers possess a form ...

Using first principles variable cell shape molecular dynamics, we predict a new structure for silica. This structure results from annealing a-quartz at pressures near a major phonon instability. The new phase is obtained by rotations of SiO4 tetrahedra producing edge-sharing SiO6 octahedra and SiO5 cuboids. This type of mechanism was proposed to account for structural transitions in silicate me...

We report single-crystalline mesoporous molybdenum nitride nanowires (meso-Mo3N2-NWs) prepared by topotactic reaction using single-crystalline molybdenum oxide nanowires. The single-crystalline nature of meso-Mo3N2-NWs was clearly observed by field-emission transmission electron microscopy. The meso-Mo3N2-NWs exhibited mesoporous structure with 45 m/g in specific surface area and 4.6 nm in aver...