A summary is presented of the methods and apparatus used ill the spectroscopic laboratories of the National Research Council for the study of electronic spectra of diatomic and polyatomic molecules including especially the study of short-lived species (free radicals). Three methods, the flash photolysis technique, the flash discharge technique, and the fast pumping of the parent compound through a high frequency discharge have been particularly useful in producing new spectra of short-lived molecules and in improving our knowledge of known spectra.
A. E. Douglas and G. Herzberg, "Apparatus for the Observation of Optical Molecular Spectra," Appl. Opt. 6, 1593-1595 (1967)