The nature of resonance phenomena in atomic and molecular systems is reviewed along with a discussion of the utilization of synchrotron radiation in studying resonance phenomena. The effects of autoionization and shape resonances on the branching ratios and asymmetry parameters for several systems are discussed. The potential and current status of threshold photoelectron spectroscopy and ion coincidence techniques are discussed.
R. P. Madden and A. G. Parr, "Resonance phenomena in molecular photoionization: impact of synchrotron radiation," Appl. Opt. 21, 179-188 (1982)