Abstract
A set of Buckingham-type potentials has been prepared specifically for the description of the compressive behaviour of the orthorhombic perovskite-structured MgSiO3 phase (space group, Pbnm). The refinement made use of structural data from high-pressure experiments, elasticity measurements, and charge distributions derived from periodic Hartree-Fock calculations. The resulting potentials account for the observed geometry up to a pressure of 10–6 GPa, and the compressibility is in good agreement with plane-wave studies up to a pressure of 150 GPa.