Mechanical and Dynamic Properties of N,N,N,N-Tetramethylammonium Dicyanamide Plastic Crystal

摘要

Elastic constants and relaxation of N,N,N,N-tetramethylammonium (TMA) dicyanamide (DCA) plastic crystal was investigated as a function of temperature using a quantum chemistry based, dipole polarizable force field. Simulations predict the [TMA] [DCA] crystal structure and dimensions in good agreement with experiment. Ion-counterion spatial distributions are used to understand the local environment and ion pairing of both ions in crystalline and liquid phases. The rotational dynamics of ions in the crystalline system are thoroughly explored. Arrest of the DCA rotational degrees of freedom is associated with the experimentally observed solid-solid phase transitions.