THE SPECTRUM OF THORIUM FROM 250 nm TO 5500 nm: RITZ WAVELENGTHS AND OPTIMIZED ENERGY LEVELS

Journal Article · Sat Mar 01 04:00:00 EST 2014 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/211/1/4· OSTI ID:22339992

Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J. ^[1]

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1. National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm{sup –1} to 1800 cm{sup –1}). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer and Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis and Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

• OSTI ID: 22339992
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 1 Vol. 211; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
ACCURACY
CALIBRATION STANDARDS
EMISSION SPECTRA
ENERGY LEVELS
FOURIER TRANSFORM SPECTROMETERS
HOLLOW CATHODES
LIGHT BULBS
NEON
RESOLUTION
THORIUM
WAVELENGTHS