Vibrationally resolved cross sections and asymmetry parameters for the photoionization of ${\mathrm{N}}_2$ with coupling between the (3${\sigma }_g$${)}^{\mathrm{-}1}$ and the (2${\sigma }_u$${)}^{\mathrm{-}1}$ channels

We have performed a vibrationally resolved two-state coupled-channel calculation using the Padé-approximant C̃-functional formalism for the ν’=0←ν’’=0, ν’=1←ν’’=0, and ν’=2←ν’’=0 vibrational transitions in the photoionization of ${\mathrm{N}}_2$ leading to the (3${\sigma }_g$${)}^{\mathrm{-}1}$$X^2$${\Sigma }_g^{+}$ and (2${\sigma }_u$${)}^{\mathrm{-}1}$$B^2$${\Sigma }_u^{+}$ states of ${\mathrm{N}}_2$${\mathrm{}}^{+}$. We have found that both the vibrationally resolved ν’=0←ν’’=0 and the vibrationally averaged asymmetry parameters in the (2${\sigma }_u$${)}^{\mathrm{-}1}$ channel are in good agreement with vibrationally unresolved experimental data. However, the theoretical results presented here do not resolve the apparent discrepancies between the vibrationally resolved and vibrationally unresolved experimental data. Coupled-channel photoelectron asymmetry parameters and photoionization cross sections in the (3${\sigma }_g$${)}^{\mathrm{-}1}$ channel were not found to be substantially different from earlier single-channel results. The results presented here demonstrate the need for the inclusion of further electronic correlation effects in order to give a more quantitatively accurate description of the photoionization of ${\mathrm{N}}_2$.