PHASE-AMPLITUDE METHOD FOR CALCULATING RESONANCE ENERGIES AND WIDTHS FOR
ONE-DIMENSIONAL POTENTIALS

Emil Y. Sidky and Itzik Ben-Itzhak

J. R. Macdonald Laboratory, Physics Department, Kansas State University,
Manhattan, KS 66506 USA

We present a method for evaluating accurate resonance energies and
widths in any one-dimensional potential. Semi-classical theory (WKB)
provides a fast estimate of resonance positions, but it can be off for
the lifetimes. Conversely, there is a multitude of numerical techniques,
solving the one-dimensional Schrödinger equation that give precise
resonance energies and widths, but they are much more difficult to
apply. The phase-amplitude method presented here yields accurate
resonance energies and widths and is as easy to apply as WKB theory.