Ab initio approach to the development of interatomic potentials for the shell model of silica polymorphs

The authors have developed a new method for deriving parameters for the shell model of silica polymorphs. All parameters for the shell model are derived in a self-consistent way from ab initio energy surfaces, polarizabilities and dipole moments of small clusters. This yields an ab initio partial charge shell model potential. The potential is demonstrated by predicting the structure of a-quartz, a-cristobalite, coesite, stishovite and the IR spectrum of a-quartz which are compared with expt. and results of the widely used potentials of Jackson and Catlow, Kramer, Farragher, van Beest and van Santen