COMPUTER MODELING THE STRUCTURE OF THE DISORDER MANGANESE DIOXIDE

Ludmila Aleshina, Pekin Vladimir

KFTT, Perosavodsk State Uinversity, pr. Lenina 33, 185640, Russia. E- mail: vdir@students.soros.karelia.ru

Keywords: Manganese dioxide, X-ray research, short-range order, computer modeling .

The structure of manganese dioxide (MNO₂) has polymophism. The following modifications are now known: a - MNO₂ - Cryptomelane, b - MNO₂ - Pyrolusite, g - MNO₂ - Ramsdellite, and e - MNO₂ .

X-ray research have shown, that the structure of a sample of manganese dioxide, received repeated pyrolyz, corresponds to modifications as b - MNO₂, and the structure of a sample received by unitary pyrolyz is in many respects similar to structure of modifications g - MNO₂ , but has other character of an arrangement cation of manganese on octahedral emptiness of the sublattice of oxygen. The analysis of the characteristics of short - range order of manganese dioxide, has shown, that, during the process of piroliz occurs the disorder of the cations (Mn++) sublattice.

The basis of modifications g - MNO₂ , has four additional vacancies for cation of manganese, and basis of modifications b - MNO₂ - two.

The purpose of researches of pyrolytic manganese dioxide, methods of computer modeling, to find - out the character of an arrangement cation of manganese on octahedral emptiness of sublattice of oxygen.

At the first stage, of the computer experiment, configurations with casual distribution cation of manganese, and also with a certain kind of the interdictions on an arrangement cation of manganese on octahedral emptiness of the sublattice of oxygen are studied. At the second stage, relaxation of a configuration, by using method of a continuous of static relaxation with the subsequent analysis of the characteristics of the short - range order of a model will be carried out.

During the computer experiments it occured, that at continuous distribution cation of manganese, on octahedral emptiness of the sublattice of oxygen, the structure similar with structure of a sample received repeated pyrolyz turns out.