On Suhl's approach to the Kondo problem

A model for the Kondo problem is studied in which the impurities are envisaged as a gas of infinitely heavy particles embedded in the gas of conduction electrons. For s-wave interactions and low impurity concentrations the electron self-energy is expressed by the impurity-electron scattering matrix which is also shown to determine the thermodynamic potantial. Using standard Goldstone diagrams Suhl's equation is derived by the summation of leading singular graphs. For a special density of states, vanishing magnetic field, and no potential scattering the dispersion equation is solved exactly.