Molecular photoionization in the linear algebraic approach: ${\mathrm{H}}_2$, ${\mathrm{N}}_2$, NO, and C${\mathrm{O}}_2$

We extend the linear algebraic method to the calculation of molecular photoionization cross sections. The formulation is primarily developed in the fixed-nuclei, Hartree-Fock, and frozen-core approximations, although correlation effects in the scattering solution are introduced through an effective optical potential. The single-center expansion and close-coupling approximations are invoked to give converged scattering solutions. Cross sections and asymmetry parameters are reported for photoionization from the ground state of ${\mathrm{H}}_2$, ${\mathrm{N}}_2$, NO, and C${\mathrm{O}}_2$. We obtain very good agreement with the Schwinger variational results of McKoy and co-workers for all molecular systems. For NO and C${\mathrm{O}}_2$, we find substantial disagreements with the Stieltjes calculations for some symmetries.