To what extent does the resonant level model describe heavy-fermion systems?

The resonant level model is applied to the heavy-fermion systems CeCu6 and CeAl3. It is demonstrated that the resonant level model, if suitably generalized to include crystal-field effects, provides an approximate fit to both the specific heat and susceptibility. This is accomplished by including the effects of the larger energies, the crystal-field splittings, first. The Kondo effect is assumed to dominate the behavior of the magnetization in the easy direction. To simulate the effect of spin fluctuations and to fit the low-temperature CeAl3 data, a temperature-dependent width is postulated