Experimental investigations of the Zeeman effect of new fine structure levels of Lanthanum and Praseodymium

• Modification of a hollow-cathode/LIF method for Zeeman effect studies
• Lande-gJ factors for some recently found energy levels of La I and Pr I were determined.
• A single excited line selected from a very dense spectrum can be easily isolated and analyzed.

Landé-g J data are given for several lines of La I and Pr I in the wavelength range 641.993 nm to 685.364 nm. Spectra were recorded in the presence of magnetic fields of about 800 G for two polarizations of the exciting laser light, perpendicular and parallel with respect to the direction of the magnetic field. We have used a hollow cathode sputtering atom source and laser induced fluorescence and/or optogalvanic detection. In this way we have determined for the first time the Landé-g J factors for some new levels of neutral La and Pr atoms. Additionally, the Landé-g J factors for other known levels of La I and Pr I were reinvestigated.