A note concerning the anharmonic corrections to Cv/3Nk in the inert gas solids at high temperature

Abstract

Expressions are derived for the linear term in the high temperature specific heat C_v for FCC lattices using the assumption that the atoms interact with central first neighbour forces only. The harmonic contribution to the lattice free energy at high T is calculated exactly, using a trace theorem derived by Salter. In addition cubic and quartic terms are retained using an extension of the earlier work of Maradudin et al (1961) due to Feldman and Horton (1967). The present formalism is used to calculate the linear term in the expansion C_v/3Nk=1+AT+ . . . for the inert gas solids Ar, Kr, and Xe using the exp-6 potential. The calculations, which include the effects of thermal expansion, are compared with experiment and to some recent calculations by Trivedi (1971), who used a less complete form for the calculation of the A coefficient.