PHOTOELECTRON-SPECTROSCOPY OF UNSTABLE MOLECULES

Recent progress in the study of unstable molecules by photoelectron spectroscopy is illustrated by considering a number of appropriate examples. The u.v. photoelectron spectra of the molecules CH2F and CH3CHF, which were prepared by fluorine atom abstraction from CH3F and CH3CH2F, are presented. The evidence used to assign the spectra, derived from the observed reaction chemistry, the vibrational structure within the photoelectron bands and ab initio calculations is reviewed. SiS is chosen as an example of a molecule prepared in the gas-phase by high temperature pyrolysis for p.e.s. study. The spectrum obtained shows clear evidence of breakdown of the one-electron ionization model. Recent chemielectron spectroscopic studies are illustrated by considering as examples the U + O2 and U + N2O reactions, and the advantages of performing laser multiphoton ionization studies on short-lived molecules, relative to single photon ionization experiments, are outlined. © 1990.