Spectrum and energy levels of doubly ionized cesium (Cs III)

The spectrum of doubly ionized cesium (Cs III) has been observed in the region 330-25000 angstrom, and the experimentally determined energy levels have been revised and extended. One thousand and ten spectral lines have been classified as transitions among 75 odd and 98 even parity levels, most of which are newly located. Most levels of the configurations 5s(2)5p(5), 5s5p(6) and 5s(2)5p(4)(5d, 6s, 6d, 7s, 5g, 6p and 4f) have been found and are theoretically interpreted including the most important configuration interactions. Low-lying levels of the 5s(2)5p(4)(7d, 7p and 5f) configurations and a few levels of other configurations have also been located. The Cs III ionization energy is found to be 267 736 +/- 30 cm(-1).