Electric-field effects on the photodetachment of H- below the N = 3 threshold

We have implemented an L2 integrable method with B-spline basis which allows us to calculate photodetachment cross sections of the H- ion in the presence of a constant electric field. The behaviour of the Feshbach resonance lying below the N = 2 and N 3 thresholds is analysed in detail. Further insight on the relative importance of autoionization and tunnelling is provided by using a stabilization procedure. Our results permit us to explain most of the experimental findings and show the existence of resonance structures previously unobserved. (author)