Asymmetries of Zeeman patterns and g-Values for neutral manganese

Abstract

Spectrograms of manganese made a t the Massachusetts In stitute of Technology with fi elds in excess of 84,000 oersteds show many Jines that exhibi t various degrees of di stortion in both the posi ti ons and the intensities of the magnetic components. The in terpretation of these asymmetric patterns has bee n made by t he approximate theory of t he partial PaschenBack effect. The g-values that have been derived fo r several energy levels of Mn I are found to con form , in most cases, with t ho e req uired for LS-co upling. A few excep t ion s to t his rule have been considered in so me detail. General tables have been computed , which will permit explanation of th e distortions in other spectra.

The first spectrum of manganese, Mn I

“…These distortions in the case of z6normalF0½° and z6normalF1½° levels were ascribed to repulsions between magnetic levels with equal M -values, belonging to adjacent levels of a spectral term, and it was shown that the theory of partial Paschen-Back effects provides a simple rule for obtaining correct g -values in spite of asymmetries in Zeeman patterns. This was elaborated by Catalán [24] who discussed in detail a dozen distorted patterns and concluded that the experimental g -values agreed with those predicted for LS coupling by Landé [7]. Finally, Espinosa [25, 26], in connection with his doctoral thesis, made a complete theoretical interpretation of the very complex Paschen-Back patterns of the z 6 P°— e 6 D and a 6 S— z 6 P° multiplets of Mn I.…”

“…The Zeeman data were most helpful in this analysis of Mn I; they have confirmed our interpretation almost completely and have permitted the designation of many terms belonging to the doublet system which was the most difficult to establish. The available Zeeman data for Mn I [6, 21, 23, 24, 27, 28, 29] prove that most of the levels arising from low-energy configurations ( d 5 s 2 , d 5 s , d 5 sp, d 6 p ) exhibit a remarkably pure LS coupling of electrons, and their g -factors are usually identical with the theoretical Landé values, within the error of measurement. Some of the upper levels of both the even and the odd configurations present anomalous g -values that may be explained by intermediate coupling or by incorrect grouping of levels in designated terms.…”

“…The letter C attached to a dozen type numbers in col. 6 indicates the lines with asymmetrical patterns which Catalán [24] analysed in detail and for which he derived proper g values. Finally, instead of type numbers, the letters P—B appear for fifty lines; these are additional lines with Zeeman patterns that exhibit partial Paschen-Back effects partially interpreted by Garcia-Riquelme et al [28].…”

“…In most cases, the Laudé type of Zeeman pattern could be recognized and for classified lines the observed Zeeman effect confirms the classification quantitatively. Because most of the Zeeman data for Mn I have been published elsewhere [23, 24, 25, 26, 27, 28] they will not be repeated here; only the type numbers [32, 34] will be listed in our list of classified lines, and the average derived g -values in our table of spectral terms.…”

Emission Spectroscopy

“…There have not been any recent observations of Zeeman effect, but a number of important papers based mainly on prewar investigations have been published: measurements of the Zeeman effect in manganese I from 2460 to 4825 A. (26), asymmetries of Zeeman patterns and y-values in manganese I (25), measurement of nearly 1000 patterns in rhenium spectra (93), a second paper on Zeeman effect and structure in tantalum 1 (11), measurement of Zeeman patterns for 540 ruthenium spark lines (94) photographed in 1940, Zeeman effects in four spectra of tellurium (53) from spectrograms made in 1936, Zeeman effect in chromium I (73) and chromium II (74), and first Zeeman data for dysprosium II (13) observed in 1940.…”