Anomalous Zeeman Effect in the D Lines of Sodium

Anomalous Zeeman Effect in the D Lines of Sodium (p. 146). 

We shall now deduce the splitting pattern of the D lines of sodium in the anomalous Zeeman effect. As we stated at p. 139, the line corresponds to the transition from a f term with inner quantum number i.e. from (1 = 1, = ), to an s term, i.e. to (I — 0, j = ) the Dg line represents a transition from 1= l,j = ) to (I — 0, j = ). 

We begin by determining Lande s splitting factors for the three terms in question. We have s — the formula 

In the two following diagrams we collect the values of the separations of the terms, taking the separation for the normal Zeeman effect as unit. That is, we write down the values mg for the upper and lo ver terms of the two lines. The values of m, like j, must be halves of odd numbers, as they are equal to —j, —j + I,, . . , j. 

The arrows indicate the possible transitions, i.e. give the positions of the lines in the Zeeman effect. Here the selection rules for the magnetic quantum number m must be taken into account. These can be deduced from the correspondence principle in exactly the same way as at p. 110 (see also Appendix XXI, (p. 308)). As m denotes the precessional motion about the direction of the field, the transition Am = +1 corresponds to the classical vibrations at right angles to H  

---