Many-body perturbation theory has been used to calculate the photoionization cross sections of the argon atom for the production of singly and doubly charged ions by photons of energy from 100 to 290 eV. Effects of correlations involving 2p excitations on both single- and double-ionization cross sections are included. Effects of relaxation and polarization on the total cross section above the 2p threshold are also calculated. The results of our calculations are compared with experiment and other calculations.

• Received 9 January 1989

DOI:https://doi.org/10.1103/PhysRevA.39.6232