The Quantum Explanation of the Zeeman Triplet

Abstract

IN his letter published in NATURE of June 27, p. 978, Prof. W. M. Hicks raises some interesting points in connexion with the quantum theory of the simple Zeeman effect. As Prof. Hicks points out, the theorem of Larmor's usually taken as the basis of the theory does not define in any manner the relation between the orbits on which the rotation is superposed in the presence of the field on one hand, and the corresponding orbits before the imposition of the field on the other. The supposition that these two sets of orbits are identical is, therefore, in no way justified on the basis of Larmor's theorem alone. It can, however, be shown from purely classical considerations (see G. A. Schott, “Electromagnetic Radiation,” Cambridge University Press, 1912, §302, p. 317) that, to the first order in terms involving the field, the two sets of orbits are identical. Schott's proof takes into consideration the induction forces which act on the moving charges during the period of establishment of the field, whereas Larmor's theorem confines itself to the so-called Coriolis forces which, as Prof. Hicks points out, act transversally on the moving charges, and hence cannot alter their energies.