The visible and near-ultraviolet emission spectrum of the CH radical has been known ever since spectra of an ordinary Bunsen burner have been taken.
For polyatomic free radicals and ions, one is dependent both for the ground states and the excited states on the study of electronic spectra to obtain the shapes and the geometrical parameters.
The citation for the 1971 Nobel Prize in Chemistry reads, 'for contribution to the knowledge of electronic structures and geometry of molecules, especially free radicals,' and therefore implies that the Prize has been awarded for a long series of studies extending practically over my whole scientific life.
