Pressure effect on anharmonic coefficients for the specific heat of alkali metals and alloys

Using the pressure effect on the two-body interaction and the mode frequencies based on the pseudopotential formalism, the anharmonic contributions to the specific heat of alkali metals and alloys under pressure are studied theoretically. The obtained results of the anharmonic coefficient for the specific heat A, defined by CΩ/3Nk=1+AT, for K, Rb and Cs under atmospheric pressure, are in good agreement with the observed data. Then, the concentration dependence of the anharmonic coefficient A is calculated for Rb1-xKx, Cs1-xKx, Cs1-xRbx solid solutions, which decreases under pressure. (orig.)