Effects of orbital degeneracy on a magnetic impurity in a nonmagnetic metal

We study the Green's-function equations for a version of the two-orbital Anderson model of a magnetic impurity, in an approximation scheme that displays the logarithmic anomalies and enables the Kondo temperature Tĸ to be calculated as a function of the parameters. The nature of the solutions is explicitly studied for large Hund's-rule exchange constant Ј, in which case we obtain the following results: If the internal exchange is treated in the Hartree-Fock approximation, it has the same effect as an enormous applied magnetic field, and the logarithmic resonances are removed far from the Fermi level, i.e., Tĸ→ .