We have studied by ab initio molecular dynamics the interconversion between oxygen deficient centers (Si-Si bond, dicoordinated silicon==Si:, and El 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.
Donadio, D., Bernasconi, M., Boero, M. (2001). Ab initio simulations of photoinduced interconversions of oxygen deficient centers in amorphous silica. PHYSICAL REVIEW LETTERS, 87(19), 195504 [10.1103/PhysRevLett.87.195504].
Ab initio simulations of photoinduced interconversions of oxygen deficient centers in amorphous silica
BERNASCONI, MARCO;
2001
Abstract
We have studied by ab initio molecular dynamics the interconversion between oxygen deficient centers (Si-Si bond, dicoordinated silicon==Si:, and El 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.
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