PHOTOIONIZATION OF 2-ELECTRON ATOMS VIA THE HYPERSPHERICAL ARTIFICIAL-CHANNEL METHOD - APPLICATION TO H- AND HE

An application of the artificial-channel method with hyperspherical coordinates to the calculation of photoionization cross sections of two-electron systems is presented. The method yields ''bound-free'' transition amplitudes and bound-state energies of any two-electron system. It obviates the separate generation of bound- and continuum-state wave functions by calculating directly the desired amplitudes. As applications, the photodetachment cross section of the H- ion and the photoionization cross section of the He atom have been calculated. The computations are compared with other theoretical calculations and with experiments. The results obtained are in excellent agreement with experimental results for all the energies considered. Of equal significance is the close agreement, attesting to the high accuracy of the method, between results obtained by using the length form for the field-matter interaction and those obtained with the acceleration form.