The Use of Ixaru's Method in Locating the Poles of the S-matrix in Strictly Finite-Range Potentials

Energies of the S-matrix poles are calculated by solving the radial Schroedinger equation numerically by using Ixaru's CPM(2) method. The trajectories of the poles in the complex wave number plane are determined for two nuclear potentials that are zero beyond finite distances. These are the Woods-Saxon form with cutoff and the Salamon-Vertse potential, which goes to zero smoothly at a finite distance[1]. Properties of the trajectories are analyzed for real and complex values of the depths of the corresponding potentials.