Turkish Physical Society 28th International Physics Congress, Turkey, pp.476
In the present work, we report the discovery of new even-parity energy levels of neutral Lanthanum atom by laser-induced fluorescence spectroscopic method based on investigating hyperfine structure (hfs) in a hollow cathode discharge lamp. The atomic La wavelengths in the spectral range from 430 nm to 742 nm have been excited by using a tunable single-mode cw ring dye laser system, operated with Stilbene-3, Rhodamine 6G, Kiton-Red, DCM and LD700 dyes.
A classification program  was used to classify the new lines including the new fine structure energy levels. The excitation wavelengths have been extracted from high-resolution Fourier transform (FT) emission spectra of La-Ar plasma providing from Laser Centre in Riga-Latvia .
During this work, the new 18 higher lying fine structure energy levels of La I were discovered with accuracies less than 0.01 cm-1 and confirmed by more than one laser excitation. The magnetic dipole hyperfine interaction constants A for the new fine structure energy levels were determined.