  An extended Anderson model, including screening channels (non-hybridizing,
but interacting with the local orbit), is studied within the Anderson-Yuval
approach, originally devised for the single-channel Kondo problem. By comparing
the perturbation expansions of this model and a generalized resonant level
model, the spin-spin correlation functions are calculated which show non-Fermi
liquid exponent depending on the strength of the scattering potential. The
relevance of this result to experiments in some heavy fermion systems is
briefly discussed.
