Photoabsorption of the neutral sodium atom: A many-body calculation

Abstract

By applying many-body perturbation theory, the effects of electron correlations are included in the calculation for the photoionization cross section of the neutral sodium atom from threshold to 16 eV for the photoejected electron energy. The improvement of the lowest-order Hartree-Fock approximation for the cross section by the first-order and second-order correlation corrections is small. The discrepancy between the experiment and the calculations at the short-wavelength side of the minimum is still not understood.