Hyperfine structure investigations of the odd configurations of lanthanum atom

The hyperfine structure (hfs) of lanthanum atom have been studied with the method of laser induced fluorescence (LIF) in the hollow cathode discharge. The investigated transitions within three spectral ranges have been excited by stabilized tunable single-mode ring dye lasers (Coherent, model 699-21), operating on Rhodamine 6G and DCM in the spectral range of 570-610 nm and 617-666 nm respectively, and on Stilbene 3 in the spectral range of 410-460 nm. The hfs magnetic dipole A and electric quadrupole B constants of more than 100 odd levels have been determined (59 of them for the first time). The hyperfine structure of the odd levels of La I has been analyzed by simultaneous parametrization of one- and two-body interactions for the system of 61 configurations. Magnetic-dipole hyperfine interaction constants A were calculated using the fine structure eigenvectors and adjusting radial integrals in a least-squares procedure which compare the calculated A constants with the experimental values. Moreover, the values of energy for the levels up to now unidentified and hyperfine structure A constants were predicted