Laser-induced "charge transfer-lattice" clusters and site-conversion near charged impurities

Theoretical analysis of the laser excitation-induced conversion of the site s accompanied by memory effect both caused by Eu3+ impurities in BaFCl crys tal was performed. A model based on a new type self-consistent "charge tran sfer-lattice distortion" states induced by charged impurities in their vici nity was considered in this connection. Here impurity field increases an eq uilibrium charge transfer with appearance of charge transfer vibronic excit on (CTVE) states. The origin of the phenomenon was explained as a result of cross-relaxation between CTVE trapped by impurity on the one hand and exci ted states of this impurity on the other. (C) 2001 Elsevier Science B.V. Al l rights reserved.