Photoionization profiles of helium autoionizing states in external DC electric fields

Electric-field effects on the doubly excited resonant structures in He grou nd state photoionization are investigated theoretically using the complex-r otation method with a B-spline-based configuration interaction (BSCI) basis . The variations of the structure profiles for the M-L = 0 components of He (2,2a), (2,3a), and (2,4a) P-1(o) and D-1(e) resonance pairs for selected DC electric field strengths are examined. The changes of the resonant energ ies, widths, Fano q-parameters, and background cross sections, are also pre sented.