Vacuum Ultraviolet Laser Spectroscopy of Molecular Autoionizing States

This paper describes a new apparatus which uses coherent vacuum ultraviolet light to photoionize molecules in a supersonic molecular beam, and energy analyzes the resulting photoelectrons by time of flight spectroscopy. The broadly tunable coherent VUV is generated by four wave sum mixing in Hg. Using this apparatus, we have studied the dynamics of autoionization for two different systems: spin-orbit autoionization in HI, and vibrational autoionization in NO. In both cases, our recent results have pointed out dramatic new features of the dynamics in these molecules.