title: Ab initio simulations of photoinduced interconversions of oxygen deficient centers in amorphous silica.
abstract: We have studied by ab initio molecular dynamics the interconversion between oxygen deficient centers (Si-Si bond, dicoordinated silicon =Si:, and E' centers) induced by UV irradiation in a-SiO2. By dynamical simulations in the excited state of a periodic model of a-SiO2 we have identified the reaction path and activation barrier for the Si-Si-->=Si: interconversion. A new competitive transformation of the excited, neutral Si-Si bond into two E' centers has been identified. Our results provide strong theoretical support to the viability of these processes, proposed experimentally on the basis of optical data only.
authors.affiliation: Istituto Nazionale per la Fisica della Materia and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Cozzi 53, I-20126 Milano, Italy. davide.donadio@unimib.it
authors.forename: D
authors.initials: D
authors.lastname: Donadio
authors.forename: M
authors.initials: M
authors.lastname: Bernasconi
authors.forename: M
authors.initials: M
authors.lastname: Boero