Local-field effects on spontaneous emission of impurity atoms in homogeneous dielectrics

The local-field corrections to the spontaneous emission rate of an impurity atom in an otherwise homogeneous dielectric are calculated by making use o f a macroscopic approach. An extension of a method introduced by Onsager an d Bottcher is presented. By distinguishing between the substitutional and i nterstitial character of impurities, the well-known empty-cavity and Lorent z local-field factors are obtained, respectively. For fluids, the substitut ional case is predicted to occur prevalently. (C) 2000 Elsevier Science B.V . All rights reserved.