Band structure and photocatalytic properties of perovskite-type compound Ca2NiWO6 for water splitting Original Research Article

Using the first-principles computations we have calculated phonon-dispersion relations and the phonon density of states for perovskite and post-perovskite phases of MgSiO3. From them using the quasiharmonic approximation we have estimated the free energies, bulk modulus and volume expansion coefficients of both structures at various pressures and temperatures. Our calculations indicate that the thermal expansivity of MgSiO3 changes very little across the phase transition. We have determined the P–T coexisting line of perovskite and post-perovskite phases.