Sequences of threshold resonances in - H scattering

Abstract

Sequences of S, P and D resonances in positron - hydrogen scattering were shown to still exist below the n = 2 H excitation threshold in a coupled-state calculation employing a large coupling scheme. The positions of the resonances were found to shift slightly away from the threshold and their widths to broaden slightly, compared with those previously determined with smaller schemes. The energy ratios and width ratios of the successive resonances of a sequence still reasonably satisfy the predicted `scaling law'.