Theory of host sensitized luminescence of rare earth doped materials II. Effective operator formulation

The crystal field potential and electron correlation terms contributing to the amplitude of the energy transfer in the case of host sensitized lumines cence are discussed. The approach is based on the double perturbation theor y, and the contributions are defined in the terms of effective operators ex pressed by unit tensor operators. In addition to one particle effective ope rators, two particle objects of second order an introduced that are complet ely new in the theory of luminescence. The radial terms of all effective op erators are defined within the perturbed function approach due to which the complete radial basis sets of one electron functions of given symmetry are taken into account. (C) 2001 Elsevier Science B.V. All rights reserved.