Procedure for obtaining microscopic mechanisms of reconstructive phase transitions in crystalline solids

Abstract

A procedure for obtaining possible microscopic mechanisms for reconstructive phase transitions in crystalline solids is described. Both strains and atomic displacements are considered, and the procedure includes user input of allowed strain tolerance, nearest-neighbor distances, and unit-cell size change. This method has been implemented in a computer program COMSUBS. We apply COMSUBS to the pressure-induced phase transition in NaCl and obtain 12 possible mechanisms, two of which are those proposed earlier by Buerger and Watanabe, respectively. Furthermore, we show how to use energy calculations to determine the height of the energy barrier for the transition.