Multiplet Structures of Transition Metal Deep Impurities in ZnS

The electronic structures of substitutional 3d transition metal (TM) impurities Ti 2+ to Cu 2+ in ZnS have been calculated from the first principles in the cluster method. The TM impurity states are found to be described well by a relatively large cluster consisting of 59 atoms. All impurity states appear in the energy gap region of ZnS and have a strong TM 3d character except those of Cu 2+ . The effects of multiplet struclure have been included by a parameter-free approach which connects the first principles results with the ligand field theory. The low-lying multiplets of 3d TM impurities in ZnS are reproduced well by the present theory.