Analysis of radiation-induced hole localisation in titanates

Hole self-trapping in technologically important BaTiO3 and SrTiO3 crystals is studied using a quantum-chemical method developed for periodic systems, e.g., crystals. The computations are carried out in the self-consistent-fie ld manner using the embedded molecular cluster model. The possibility of sp ontaneous hole self-trapping is estimated by employing an analytical proced ure based on the energetical favourability principle. Our results support t he self-trapping of radiation-induced hole in BaTiO3 crystals while such an outcome is not predicted for SrTiO3 crystals. Computational results are di scussed in the light of available experimental data on light-induced absorp tion spectra measurements in BaTiO3 crystals. (C) 2001 Elsevier Science Ltd . All rights reserved.