This paper reports dynamical mean field calculations for the periodic Anderson model in which the conduction band is coupled to phonons. Motivated in part by recent attention to the role of phonons in the $\gamma$-$\alpha$ transition in Ce, this model yields a rich and unexpected phase diagram which is of intrinsic interest. Specifically, above a critical value of the electron-phonon interaction, a first order transition with two coexisting phases develops in the temperature-hybridization plane, which terminates at a second order critical point. The coexisting phases display the familiar Kondo screened and local moment character, yet they also exhibit pronounced polaronic and bipolaronic properties, respectively.Comment: 4 pages, 6 figure

Bimetallic oxalates are layered molecule-based magnets with either ferromagnetic or antiferromagnetic interactions between transition metals M͑II͒ and MЈ͑III͒ on an open-honeycomb lattice. Some Fe͑II͒Fe͑III͒ bimetallic oxalates exhibit magnetic compensation ͑MC͒ at a compensation temperature T comp Ϸ 30 K below the ferrimagnetic transition temperature T c Ϸ 45 K. To see if MC is possible in other bimetallic oxalates, we construct a theoretical model for bimetallic oxalates that exhibit antiferromagnetic interactions. By varying the M͑II͒ and MЈ͑III͒ average orbital angular momentum, which can be controlled by the choice of interlayer cations, we find regions of MC in the families M͑II͒Mn͑III͒ with M = Fe, Co, or Ni and V͑II͒MЈ͑III͒ with MЈ = Cr or V but not in the family M͑II͒Ru͑III͒ with M = Fe or Cu.

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