NEW DIAGRAM TECHNIQUE FOR THE ANDERSON MODEL

A generalized Wick theorem for the Anderson model is formulated. On th is basis, the diagram technique fbr the temperature Green's function a nd the thermodynamic potential is developed. Particular attention is p aid to the region of strong coupling of an impurity atom with a metal. The Dyson equations are solved and the impurity Green's function is e xpressed in terms of the mass operator. The contribution to the mass o perator and corrections to the energies of localized states are obtain ed in the second order of perturbation theory.