Quasibound states in an electric field

Abstract
The Lippman-Schwinger equation in one dimension is solved for the cases of one and two δ wells in an electric field. At low field the field dependence of the quasibound levels behaves in accordance with perturbation theory, while the levels are ionized at high fields. The two-well case exhibits the onset of a Stark ladder. In both cases there is evidence for a positive-energy-resonance structure which becomes suppressed as a δ-well lattice is formed.