FINE-STRUCTURE MEASUREMENTS FOR NEGATIVE-IONS - STUDIES OF SE- AND TE-

This paper comprises a comparison of experimental methods used for det ermining fine-structure splittings in negative atomic ions. The compar ison is based on experimental data for the fine-structure splittings o f the 4p(5) P-2 term of Se- and 5p(5) P-2 term of Te- obtained by sing le-photon detachment and three-photon detachment in a Raman coupling s cheme. The result for the J=3/2-1/2 splitting in Se- is found to be 22 78.2(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.