Bond-conversion model for photoinduced effects in glassy Ge-S chalcogenides

A bond-conversion model for the photostructural changes in the photolumines cence and Raman spectra is proposed by which bonding configurations are opt ically rearranged due to the formation of a new covalent bond in the photoe xcited state. The essential role in this model is of the lone-pair electron s of the chalcogen atoms. The important feature of this model that is subst antially different from the other models is the assumption of the covalent bond formation before bond breaking, but not following the breaking, as sta ted in other works. (C) 2000 Elsevier Science B.V. All rights reserved.