High frequency limits of the two-electron photoionization cross sections

Several cross sections of two-electron processes at high but nonrelativistic photon energies ω are considered, which are expressed solely via the initial state wave function of the ionized two-electron object. The new high precision and locally correct nonvariational wave functions describing the ground and several lowest excited states of H^-, He and helium-like ions are used in calculations of different cross sections in the pure dipole approximation and with account of first order corrections in ω/c², and a number of the cross sections' ratios. The dependencies of all these quantities on the nuclear charge Z and the principal quantum number n (for 1 < n < 5) of the initial state excitation are studied.