Atomistic modelling of radiation effects: Towards dynamics of exciton relaxation

This brief review is focused on recent results of atomistic modelling and s imulation of exciton related processes in ionic materials. We present an an alysis of thermal fluctuations of the electrostatic potential in cubic ioni c crystals and their relation to formation of a tail in the electron densit y of states and localisation of electronic states. Then the possible 'fast' mechanism of formation of F-H pairs in KBr as a result of decomposition of relaxing excitons is discussed. We briefly describe some ideas related to the possibility of coherent control of exciton decomposition into Frenkel d efects in alkali halides. Next we turn to the results of modelling of excit on excitation and localisation at the low-coordinated surface sites of MgO. And finally, we present the results of quantum-mechanical simulation of pe roxy linkages and their reaction which creates oxygen molecules in silica. (C) 2000 Elsevier Science B.V. All rights reserved.