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The study on the phase transition of a solid is fundamentally not easy, for the problems such phase transition path and the temperature/pressure dependences. The most advanced computational technique developed in literature for the phase transition of a solid may be the metadyamics plus NPT molecular dynamics. Without the molecular dynamics simulation, the solid state nudged elastic band developed in literature also can be used to study the phase transition of a solid. The simple way: i) do the calculations of the enthalpies versus volumes of two phases to get the pressure of phase transition, or ii) Based on the quasiharmonic approxmiation, do the calculations of the Helmholtz free energy versus volumes and temperatures of two phases to get the temperature and pressure of phase transition.
