BEYOND THE ISOTROPIC-MODEL APPROXIMATION IN THE THEORY OF THERMAL-CONDUCTIVITY

By the use of an iterative method the linearized phonon-Boltzmann equa tion for a dielectric solid subjected to a thermal gradient is solved in the frame of three-phonon interactions. In this way it is possible to calculate the thermal conductivity of rare-gas solids starting from the pair potential and accounting for the real Brillouin zone of the lattice. The numerical results are in full agreement with experiment a nd represent a considerable improvement with respect to those previous ly deduced for an isotropic solid.