Thermodynamic Green's Function Approach to Impurity Conduction. II. ac Conduction

The thermodynamic Green's function method is applied to the problem of ac impurity conduction in semiconductors. Both direct and indirect photon absorption processes are studied. A special technique is devised for the conctruction and calculation of the diagrams for the auto‐correlation function of the dipole moment operator. New results for the direct photon absorption conductivity are presented.