STRONG AND VERY STRONG COVALENCY EFFECTS ON THE LIFETIME OF MN2+ IN II-VI COMPOUNDS

Abstract A ligand field model is proposed for the radiative lifetimes or dipole strengths of d 5 ions in tetrahedral symmetry. The dipole strength of the transition from the fluorescent orbital triplet state 4 T 1 to the ground state 6 A 1 is given by second-order perturbation schemes involving the dipole moments and the molecular spin-orbit interactions for the electrons of the metal and of the ligands. In the case of Mn 2+ in ZnS, ZnSe and ZnTe, it is shown that the multielectronic wave functions 4 T 1 and 6 A 1 have approximately the same degree of covalency and that the dominant operator governing the lifetimes of Mn 2+ is the spin-orbit interaction of the p-electrons of the ligands.