Effects of Shape Resonances on Vibrational Intensity Distributions in Molecular Photoionization

We report striking non-Franck-Condon vibrational intensity distributions associated with the shape resonance in the 5σ photoionization channel of CO. This example confirms the recent theoretical prediction that shape resonances will couple significantly with vibrational motion, leading to different resonance energies and profiles, and non-Franck-Condon intensities in alternative vibrational channels. Analogous effects are expected in connection with the widespread occurrence of shape resonances in both innershell and outershell molecular photoionization spectra.