%0 Journal Article %T The Puzzle of the La I Lines 6520.644 Å and 6519.869 Å %A Laurentius Windholz %A Bettina Gamper %A Przemys£¿aw G£¿owacki %A Jerzy Dembczy¨½ski %J Spectral Analysis Review %P 10-18 %@ 2331-2106 %D 2014 %I Scientific Research Publishing %R 10.4236/sar.2014.23024 %X

The strong La line 6520.644 ? is present in a Fourier Transform Spectrum (signal to noise ratio of 240), but its wavelength in commonly used tables (e.g. [1]) is given as 6520.770 ?, while in [2] the wavelength is given as 6520.74 ?, unclassified, with the remark ¡°h¡± (hazy). The line could not be classified using known energy levels of the La atom (La I) and its first ion (La II). It appears as a single broadened peak. By a combination of laser optogalvanic spectroscopy, laser-induced fluorescence and Doppler-reduced saturation spectroscopy we could introduce a new even parity La I energy level, 35449.041 cm -1, J = 13/2, with hyperfine (hf) constants A = ?8.0(5) MHz, B = 10(10) MHz. For a second, up to now unknown neighbouring La I line (wavelength 6519.869 ?) we introduced another even parity energy level involved in the formation of the line, 41207.994 cm -1, J = 13/2, A = 91.6(5) MHz, B = 170(50) MHz. We tried also to explain why in old tables the wavelength given was so different.

%K Lanthanum %K Energy Levels %K Laser Spectroscopy %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=48374