Effect of Temperature on Structural Properties of Rare Erath Chalcogenides

In this study, the calculated results of the structural properties of ThX (X=S and Se) rare earth chalcogenides in rocksalt structure (B1) are presented. The Realistic Interaction Potential Approach (RIPA) model has been developed and used. A sudden collapse in volume has been occurred at phase transition pressures. At compressed volumes, these compounds are found in CsCl phase. Phase transition pressures have been reported at room and high temperature range 0-1000K. The phase transition pressures and associated volume collapses obtained from present potential model show a generally better agreement with available experimental and others results. Keywords: Phase transition, High pressure, Crystal structure, Elastic properties