Superposition model calculation of zero-field splitting of Fe3+ in LiTaO3 crystal

The second-order zero-field splitting (ZFS) parameter b(2)(o) of the Fe3+ ion centre at the Li site, the Ta site and the structural vacancy site in the LiTaO3 crystal are calculated using the empirical superposition model. The fourth-order ZFS parameters b(4)(o), b(4)(3) and b(4)(-3) are also calculated at the Li and Ta site, respectively. The calculated b(2)(o) of Fe3+ ion at the Li site agrees well with the experimental one. It is concluded that the Fe3+ replaces the Li+ ion rather than the Ta5+ ion in the LiTaO3 crystal. This conclusion confirms the site assignment from the electron nuclear double resonance experiments.