Novel a b i n i t i o self-consistent-field approach to molecular solids under pressure. I. Theory

A fully ab initio wave-function based procedure for the study of molecular solids under high pressure is presented. The method includes all many-body interactions, takes maximum advantage of symmetry to reduce computation, and is designed to allow for the direct study of reactions occuring in molecular crystals placed under high pressure. Furthermore, the approach is completely general, allowing for its application at either semiempirical or exact levels of calculation. As an aside to this work, we also demonstrate the efficacy of using an algebraic approach, instead of the conventional series expansion, to calculate the elements of the inverse overlap matrix for the crystal.