Calculation of electronic ion polarizability and parameters of interionic repulsion in LiNbO3 crystals

A method for calculating the anisotropy of the electronic polarizability of O2- ions in oxygen octahedral ferroelectrics has been proposed. It is show n that, in the case of mixed ion-covalent bonds in the crystal, the calcula tion of the polarizability within the approximation of isolated ions gives incorrect results. The principal components of the polarizability tensor fo r the O2- ions and the electronic polarizability of the Nb5+ ions are calcu lated for the LiNbO3 ferroelectric. Analysis of the stability of the LiNbO3 structure confirms the results obtained. (C) 2000 MAIK "Nauka/ Interperiod ica".