Configuration interaction and intensity of crystal field spectra of the tetrahedral Ni 2+ Ion

The tetrahedral crystal field acting on the F‐state ion Ni 2+ in ZnO mixes the odd parity states of excited 3d 7 4p and 3d 7 4f configurations with the even parity states of 3d 8 configuration and this mixing has some contribution to the intensity of electric dipole transition between crystal field levels. The contribution of such configuration interaction to the oscillator strength for transitions from the lowest crystal field level T 1 to the higher ones is estimated within the framework of crystal field theory using the powerful Racah method and Richardson function for the radial integrals. The results indicate that such contribution to the intensity is quite significant; it accounts for an appreciable amount of intensity observed particularly for one of the transitions T 1 → T 2 . Moreover, this contribution to all the three transitions considered, is found to be much larger than the intensity for the corresponding magnetic dipole transitions.