The discovery, refinement, and quantum interpretation of atomic energy levels has been the principal goal of fundamental research in atomic spectra during the past quarter century. Analyses of the fine structure of spectra have revealed the electronic structures and the ionization potentials of atoms and ions; studies of hyperfine structure of spectral lines have yielded data on the mechanical, magnetic, and electric-quadrupole moments of atomic nuclei. This paper rates the fine structure analyses of 504 spectra of 84 chemical elements, and quotes the nuclear moments for 184 isotopic species.
WILLIAM F. MEGGERS, "Fundamental Research in Atomic Spectra," J. Opt. Soc. Am. 41, 143-148 (1951)