Molecular Simulation of Solid-Solid Phase Transitions

Applications of dl_poly to solid-solid phase transitions are reviewed, with particular attention to how details of the mechanisms of the transitions may be extracted from molecular dynamics simulations. Two examples in molecular crystals are discussed: the order-disorder transition of p-terphenyl initiated at around 200K by the unlocking of ring flipping; and the rotator phases of n-alkanes with around 20 carbon atoms per chain, showing distinct molecular mechanisms in the dynamics just below the melting points of odd and even chains. Covalent-ionic materials are represented by an application to an aluminophophate molecular sieve, AlPO_4-5