Rayleigh-Schrodinger perturbation theory for resonance tunneling

We calculate accurate tunnel resonances by means of-standard Rayleigh-Schrodinger perturbation theory, exactly as if they were ordinary bound states. We choose one-dimensional barriers with a single maximum to test the convergence properties of the perturbation series. The method consists of an expansion of the potential-energy function about its maximum and a dilatation of the coordinate by means of a complex scaling parameter completely determined by the curvature of the barrier. (C) 1996 American Institute of Physics.