Experimental hyperfine structure investigation of atomic la

Optogalvanic laser spectroscopy has been applied to measure the hyperfine structure of 19 spectral lines of La I in the wavelength regions from 570 to 590 nm and 700 to 825 nm. Experimental hyperfine structure constants A and B of the isotope¹³⁹La have been measured for 16 levels of odd parity. From those values six magnetic dipole and ten electric quadrupole constants have been determined for the first time. Some disagreements with previously obtained values are discussed.