Abstract: Taking slight magnetic interactions (including spin-spin interaction, spin-otherorbit interaction and orbit-orbit interaction) into account and by using complete diagonalization method and perturbation theoretical method, zero-field splitting (ZFS) of 4B₁ and ²E states for 3d³ ions was studied in tetragonal symmetry crystal field. The result show that ZFS of the ⁴B₁ state is linear to the slight magnetic interaction parameters, and ZFS of ²E state mainly depends on spin doublets.

Key words: slight magnetic interactions, diagonalization, zero-field splitting, perturbation formula