In the emission spectra of beam-foil excited oxygen and fluorine, it has been possible to assign lines to the quartet term systems of doubly excited three electron ions. A comparison with known spectra of singly excited four-electron systems turned out to be useful for line identification. The measured wavelengths are compared to theoretical predictions.
Dedicated to Prof. Dr. A. Steudel on the occasion of his 60th birthday
We thank the staff of the Bochum accelerator for running the machine. The help of H. Hellmann, G. Hubricht and B. Müller with the experiment and of H.H. Bukow and K.P. Reichelt who prepared the excellent foils is gratefully acknowledged.