Fine-structure measurements for negative ions: Studies of Se- and Te-

This paper comprises a comparison of experimental methods used for determining fine-structure splittings in negative atomic ions. The comparison is based on experimental data for the fine-structure splittings of the 4p5 2P term of Se- and 5p5 2P term of Te- obtained by single-photon detachment and three-photon detachment in a Raman coupling scheme. The result for the J=3/2-1/2 splitting in Se- is found to be 2278.2(2) cm-1, while the J=3/2-1/2 splitting in Te- is 5004.6(5) cm-1. A variety of experimental approaches to fine-structure measurements are briefly discussed. In many atomic negative ions the perspectives for improvements in the determination of fine-structure splittings are in the range of two to three orders of magnitude. © 1996 The American Physical Society.