The third spectrum of manganese was investigated from 500 to 2500 Å with 2-m normal-incidence vacuum spectrographs. The wavelengths of the spectral lines, excited in both sliding-spark and condensed-spark discharges in helium, were determined with an uncertainty of ±0.006 Å. Forty-six energy levels belonging to 23 terms were found and one energy level was redesignated. Four hundred and eight spectral lines were Classified as transitions between levels of the 3<i>d</i><sup>5</sup>, 3<i>d</i><sup>4</sup> 4<i>s</i>, and 3<i>d</i><sup>4</sup> 4<i>d</i> configuration and levels of the 3<i>d</i><sup>4</sup> 4<i>p</i> configuration.
STANLEY J. YAROSEWICK, JAMES J. DAVIA, and FRANK L. MOORE, JR., "New Energy Levels of Doubly Ionized Manganese (Mn III)," J. Opt. Soc. Am. 61, 732-739 (1971)