Theory of host sensitized luminescence of rare earth doped materials. I. Parity onsiderations

The theory of host sensitized luminescence based on the electrostatic model of interaction is extended beyond the free ionic system approximation and improved by the contributions that break the limitations of the single configuration approximation. The approach is based on A double perturbation theory and defined in the terms of tensor operators. The parity requirements and consequent selection rules are discussed in the case of various contributions to the energy transfer probability defined up to the third order of perturbation expansion.