In this work, X-ray studies of the amorphous oxide ®lms obtained by thermal evaporation of WO 3 powder in a vacuum and by anodic oxidation were carried out. X-ray diffraction patterns were obtained in the symmetric re¯ection geometry on a DRON-4 diffractometer (Mo K radiation, LiF monochromator) in automatic mode. Molecular dynamics simulation of amorphous tungsten oxide atomic con®gurations has been carried out in the micro-canonical ensemble (NVE) for N = 208 atoms and N = 624 atoms, in a cubic cell, using pairwise Born±Mayer interaction potentials and periodic boundary conditions. One of the purposes of the present work is to analyze the in¯uence of the parameters and the cutoff of the interaction potentials on the interatomic distances. The values obtained in the molecular dynamics simulation for the pair functions D(r) are compared with the experimental data for amorphous oxides in order to choose the most convenient aforesaid values. The values of the average interatomic distances and the coordination numbers obtained by both methods are also compared. The result shows that the tungsten subsystem can be well reproduced using the potential cutoff radius of about 4 A Ê , but the oxygen subsystem can be well reproduced when the cutoff of the potential for the WÐO pairs is equal to 2.8 A Ê . The con®guration built during the molecular dynamics experiment consists of distorted octahedra. These octahedra form chains, as in the WO 3 phases of type ReO 3 , and hexagonal rings, of the same type as in the WO 3 (1/3)H 2 O phase, when we extract (1/3)O at every WO 3 unit. The pair function D(r) and scattering intensity I(s) distribution curves calculated for simulation con®gurations show a satisfactory agreement with experiment.
Quantum-chemical calculations of the parameters of the nM+・NbClF2−6 type particles have been performed, where M stands for Na, K, Cs and n = 0 - 6. Under certain conditions such particles may exist in melts of alkali metal chlorides.Within the framework of this approximation, compositions for themost stable particles in molten salts were obtained. Relative stability of the particles containing the NbF−6 , NbClF2−6 , and NbF2−7 complexes has been calculated. Energies and some other characteristics of the electron structure and the particle geometry structure were determined depending on the n and M values. For estimation of the third sphere’s influence, the systems (M2NbF7 +8MCl) and (M2NbF7 +15MCl) are surveyed. The chlorine anion enters the first coordination sphere in the Nasystem only, i. e. in this system the true complex NbClF3−7 is formed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.