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 3d5, 3d4 4s, and 3d4 4d configuration and levels of the 3d4 4p 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)