Computer modelling of B₂O₃. I. New interatomic potentials, crystalline phases and predicted polymorphs

Atomistic simulation techniques are applied to the study of crystalline B 2 O 3 . New interatomic potentials are derived by fitting to ab initio energy surfaces derived from both periodic boundary conditions and molecular calculations, to which we add the restraints produced by the observed crystal structures. A novel approach based on linear programming (LP) methodology is used in these fitting procedures. We find that the best potentials have terms which are coordination number dependent. Our potentials are able to reproduce the crystal structures of both polymorphs of B 2 O 3 . Moreover, we predict the stability of new polymorphs with high boroxol ring contents which may be related to the structures of vitreous phases.