Calculation of ion electronic polarizability and interionic repulsion in LiNbO3 crystals

The methodology for calculating anisotropy of the O2- ion electronic polarizability in the oxygen-octahedron ferroelectrics is considered. It is shown that by the mixed ion-covalent character of intercrystalline bonds the calculation of the polarizability in the approximation of independent ions leads to incorrect results. The values for the main components of the O2- ions polarizability tensor are calculated for the LiNbO3 ferroelectric, the probable value for the Nb5+ ions electronic polarizability is determined. Verification of the data obtained is carried out on the basis of the analysis of the LiNbO3 structure stability