Anharmonic Specific Heat of Crystalline NaCl

The anharmonic contributions to the specific heat of crystalline NaCl have been evaluated in a localized model characterized by a pseudo potential and direct Brillouin zone sums. The numerical results indicate that the anharmonic contributions to a thermodynamic quantity such as specific heat converge rapidly with respect to the chosen number of normal modes N. The approximately converged results are compared with experiments and with calculations by others.