Photoionization of Sodium, Lithium, and Potassium by a Pseudopotential Method

A pseudopotential formalism is used to calculate the cross section for photoionization of sodium, lithium, and potassium for ejected electron energies from threshold to about 15 eV. Both the dipole length and dipole velocity matrix forms are computed. For sodium, the dipole length results are in good agreement with experiment away from the lowest threshold. The dipole velocity results for sodium, on the other hand, severely underestimate the cross section except very near threshold. For lithium, the dipole length and velocity results are less than the experimental results but agree well with other theoretical results. For potassium, the cross section exhibits the general shape of experimental curves.