Results are presented for 120 Zeeman patterns in Gd II, from which <i>g</i> values for 67 levels are calculated. The problem of determining the magnetic field strength to a sufficient accuracy is discussed. The phenomenon of mixing of polarizations is attributed to scattering in the light source. The predictions of Smith and Wybourne are found to agree within experimental error for 18% of these levels and within 2% for 77% of them. An attempt is made to reassign the percentage composition of the levels <i>y</i><sup>8</sup><i>P</i>, <i>Z</i><sup>8</sup><i>P</i>, <i>z</i><sup>8</sup><i>F</i> and <i>z</i><sup>10</sup><i>D</i>, for which the observed <i>g</i> values differ markedly from those predicted. Finally the composition of the even level, 4<sub>5/2</sub>, is discussed.
D. DESMARAIS, O.M.I and ERIC H. PINNINGTON, "Zeeman-Effect Investigations in Singly Ionized Gadolinium (Gd II)," J. Opt. Soc. Am. 57, 1245-1251 (1967)