To explore the autoionization life times of the Henning diffuse and Henning sharp Rydberg series in CO2, we performed photoionization calculations very similar to those reported in Ref. at the equilibrium geometry of the CO2 molecule. We employed the multichannel Schwinger configuration interaction (MCSCI) variational method , which has been previously used to study the photoionization of CO2 . In these calculations, the final-state fixed-energy photoelectron wave functions were represented on a single-center expanded grid, with 𝑙 max = 100, that terminated at 𝑟 max = 60 Å, which was large enough to describe a number of Rydberg states below each ionization threshold. The full N-electron ionized state was represented as a closecoupling expansion containing a sum of the products of (N -1)-electron ion state wave functions with one-electron photoelectron continuum wave functions. The ion channels used in the close coupling calculation included the four valence ion states,