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Revised interpretation of the Na I EUV absorption spectrum



Alexander Kramida


Spectral data for neutral sodium were recently compiled by Sansonetti (2008 J. Phys. Chem. Ref. Data 37 1659). In that compilation, some of the energy levels of the 2p53snl configurations were quoted from the studies of the absorption spectrum in the extreme ultraviolet (EUV) region, while others were quoted from beam-foil and laser-spectroscopy studies of emission in the visible region. These two sets of data partially overlap. However, in Sansonetti (2008) the energy levels observed in both types of studies were not recognized as being the same entities and were listed as different quantum states, interpreted in different coupling schemes. In addition, the analysis of the absorption spectrum was based on an oversimplified theoretical model and is incomplete. The present work identifies the energy levels commonly observed in absorption and emission studies and provides a consistent description of the 2p53snl energy levels. As a result, about a hundred energy levels are revised. In particular, the connection of the quartet level system with the ground state is firmly established based on absorption studies.
Journal of Physics B-Atomic Molecular and Optical Physics


atomic energy levels, classified lines, absorption spectrum, neutral sodium


Kramida, A. (2010), Revised interpretation of the Na I EUV absorption spectrum, Journal of Physics B-Atomic Molecular and Optical Physics, [online],, (Accessed May 19, 2024)


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Created September 27, 2010, Updated April 7, 2024