Lattice- and Molecular-Dynamics Studies of Phase Transitions in CsLiSO4

摘要

We report results of a simulation of the phase transitions in CsLiSO4. These arebased on our previously developed method for calculating parameter-free potential-energy surface for ionic molecular crystals. Our lattice-dynamical and molecular-dynamics studies show that the room-temperature (Pnam) phase is unstable and transforms to the observed low-temperature (P 1 12, In ) phase over approximately 200-280 K. The unstable modes of the Pnam phase have maximum instability at the zone center, which indicates a possible phase transformation without a cell