Calculated optical absorption spectra of Ni2+-bearing compounds

The transition energies responsible for optical absorption spectra can be o btained by crystal-field analysis, but the transition intensities are notor iously difficult to calculate. This paper examines the basic ingredients of the calculation of optical spectrum intensities. Magnetic dipole and elect ric quadrupole transitions intensities are evaluated, as well as the direct d (Ni2+) to p (O2-) electric dipole transitions. All these contributions a re shown to be small in the optical range, so that spectral intensities are due to the mixing of odd orbitals. with the Ni2+ 3d(n) states.