The Paschen-Back Effect of Hyperfine Structure
The study of the Paschen-Back effect in hyperfine structure is of particular interest as it is the only possibility to verify the complete theory of the gradual change of the Zeeman effect from weak to strong fields, as there are no suitable multiplets available for this purpose. The theory of the Zeeman effect for any field strength has been studied by Heisenberg and Jordan [Zeits. f. Physik. 37, 263 (1926)] and by Darwin [Proc. Roy. Soc. A115, 1 (1927)] for the case of ordinary multiplets. There may be shown to be a very close analogy between ordinary multiplets and the hyperfine structure separations, the former being due to the interaction between the total extranuclear moment and the nuclear moment.
© 1929 The American Physical Society. Received 25 November 1929. We are very much indebted to Professor E. Back and Dr. J. Wulff for providing us with the results of their excellent work on this line. The calculated values of the positions and intensities are in complete agreement with the observed values, the two weakest of the "forbidden" components not being observed due to their small intensity and two of the strong parallel components not being resolved due to their proximity.
Published - PhysRev.34.1499.pdf