This review is devoted to a discussion of laboratory measurements of ionization, fluorescence, and photodetachment. The review is limited to molecules of aeronomic interest but excludes atoms. The section on photodetachment includes only work which has appeared since 1964. Current data are presented on photoionization cross sections, dissociative ionization cross sections, cross sections for the excitation of particular states of ions, relative vibrational excitation probabilities, photodetachment cross sections, angular distributions of electrons from photoionization, and dissociative excitation of neutral molecules. Some suggestions are made for further work.