Calculation of double photoionization of helium using the convergent close-coupling method.

Abstract

We use the convergent close-coupling formalism to calculate the double-to-single-photoionization cross-section ratio in helium for photon energies from threshold up to 400 eV. Our results for the velocity and acceleration forms of the electromagnetic interaction operator are very close, and lie in between the measurements of D{umlt o}rner {ital et} {ital al}. [Phys. Rev. Lett. {bold 76}, 2654 (1996)] and Levin {ital et} {ital al}. [Phys. Rev. Lett. {bold 76}, 1220 (1996)]. {copyright} {ital 1996 The American Physical Society.}