Analysis of the complex (5s5p(2)+5s4f5p+5s(2)5d)-(5p(3)+5s5p5d+4f5p(2)+5s(2)6p+5s(2)5f) transition array of eight-times ionized lanthanum (La IX)

The spectrum of lanthanum was recorded in the 300-1240 Angstrom region on a variety of normal incidence and grazing incidence spectrographs. The sourc es used for exciting the spectra were either a conventional triggered spark or a laser produced plasma. The analysis of complex (5s5p(2)+5s4f5p+5s(2)5 d)-(5p(3)+5s5p5d+4f5p(2)+5s(2)6p+5s(2)5f) transition arrays was carried out . All these odd parity configurations have been studied for the first time. Sixty out of sixty-two possible levels in this odd parity system were esta blished. Five levels belonging to the 5s4f5p even parity configuration, not established in the earlier study, have also been found and the level value of the 5s4f5p (2)G(7/2) was revised 155 additional lines have been classif ied in the 363-870 Angstrom region. The measured energies were satisfactori ly interpreted by least-squares- fitting parametric Hartree-Fock calculatio ns.