Ground state properties of the two impurity Anderson model in a 1/N expansion

The intersite contribution to the ground state energy for the two impurity Anderson model is calculated to first order in 1/N. The dependence of this contribution on the interimpurity separation has an R^?1 or R^?3 envelope for distances smaller or larger than a length ν_F/T_A ranges from a value equal to the bare ?-level position (in the weak valent regime) to the Kondo temperature (in the local moment limit).