Computational investigation into the phase transitions from AlPO4-H3

Abstract

Molecular dynamics simulation approach has been used to investigate the phase transitions from aluminophosphate AlPO 4-H 3. Derived from AlPO 4-H 3 , several hypothetical models of its high-temperature phases are designed through removing the bridged water molecules and changing the up-down connected sequences of T-sites in the 4-membered rings. Full geometry optimizations are performed to obtain structural parameters for the models that are compared to the reported data, and their structure features and thermodynamic stabilities have been discussed. The simulation study suggests that AlPO 4-H 3 is energetically favored to transform to AlPO 4-C, and then to AlPO 4-D as well as to other novel hypothetical 3D open-frameworks.