Energy levels and hyperfine structures in the (5d + 6s)3 configurations of La I

Abstract

The near-infrared region of the lanthanum spectra was recorded, between 3500 and 14 500 cm^-1, using a Fourier transform spectrometer. We report here the results concerning the classification of the even configurations (5d + 6s)³ of the first spectrum. 35 out of the 37 existing levels are now known. We performed the theoretical interpretation of the energies and Landé factors and we used the intermediate- coupling eigenfunctions to compute the angular part of the hyperfine interactions. From our measurements and earlier experimental results, the magnetic hyperfine constants of 29 even levels are known; we discuss the values of the radial hfs parameters that we deduced.