Model structure of perovskites: cubic-orthorhombic phase transition

We extend the revised global parametrization method (revGPM) of orthorhombic perovskites with Pbnm symmetry to describe the changes in the lattice parameters and internal atomic coordinates within a broad range of structural distortions, including the vicinity of the orthorhombic-cubic phase transition. The applicability of the revGPM in the prediction of the evolution of the structural parameters under increasing hydrostatic pressure is demonstrated through test calculations performed for geophysically important perovskites. The present results are compared with the available theoretical and experimental data.