Based on the theory of the partial Paschen-Back effect a quantitative explanation is given of the fact, recently discovered by the authors, that an atomic energy level of Mn I, namely z6F°1½, has two different values for the Landé splitting-factor g: one for each pair of the magnetic levels M= ±1½ and ±0½.
Attention is called to the fact that g-values, in cases such as those observed in Mn I, experience important alterations when the magnetic field is increased from about 40,000 oersteds, which is the magnitude of fields used in the past, to about 80,000, as actually used in observing Zeeman patterns at M.I.T. for the purpose of analyzing spectra.
It is pointed out that if g-values accompany a list of term-designations and term-values, it is desirable to specify the magnitude of the magnetic field to verify the correctness of the designations given in the analysis of the spectrum. Otherwise any alterations which the g-values may undergo will not be correctly interpreted.
MIGUEL A. CATÁLAN and RAFAEL VELASCO, "Changes in g-Values, in a Spectrum, for Different Magnetic Fields," J. Opt. Soc. Am. 40, 653-654 (1950)