Molecular dynamics simulation of reconstructive phase transitions on an anhydrous zeolite

The structural transformation of a framework aluminosilicate, Li-ABW, is studied using molecular dynamics. The calculations are carried out by applying the method presented by Martoňák et al. [Phys. Rev. Lett. 90, 075503 (2003)], that allows for the exploration of the Gibbs free energy as a function of the cell parameters by history-dependent dynamics. We show that this technique allows for an extensive exploration of the phase space also for complex polyatomic material, such as a zeolite, and allows for the successful prediction of a reconstructive phase transition at the pressure and temperature of experimental relevance. In particular, we observe a reconstructive transition from anhydrous Li-ABW to eucryptite at the temperature of ∼920 K, as experimentally observed. The steps initiating the transformation and the transition pathway are discussed.