Accurate Ritz wavelengths of parity-forbidden [Fe II], [Ti II] and [Cr II] infrared lines of astrophysical interest

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dc.creatorAldenius, M.
dc.creatorJohansson, S.
dc.date2007-03-07
dc.date.accessioned2026-07-07T10:21:54Z
dc.date.available2026-07-07T10:21:54Z
dc.descriptionWith new astronomical infrared spectrographs the demands of accurate atomic data in the infrared have increased. In this region there is a large amount of parity-forbidden lines, which are of importance in diagnostics of low-density astrophysical plasmas. We present improved, experimentally determined, energy levels for the lowest even LS terms of Fe II, Ti II and Cr II, along with accurate Ritz wavelengths for parity-forbidden transitions between and within these terms. Spectra of Fe II, Ti II and Cr II have been produced in a hollow cathode discharge lamp and acquired using high-resolution Fourier Transform (FT) spectrometry. The energy levels have been determined by using observed allowed ultraviolet transitions connecting the even terms with upper odd terms. Ritz wavelengths of parity-forbidden lines have then been determined. Energy levels of the four lowest Fe II terms (a$^{6}$D, a$^{4}$F, a$^{4}$D and a$^{4}$P) have been determined, resulting in 97 different parity-forbidden transitions with wavelengths between 0.74 and 87 micron. For Ti II the energy levels of the two lowest terms (a$^{4}$F and b$^{4}$F) have been determined, resulting in 24 different parity-forbidden transitions with wavelengths between 8.9 and 130 micron. Also for Cr II the energy levels of the two lowest terms (a$^{6}$S and a$^{6}$D) have been determined, in this case resulting in 12 different parity-forbidden transitions with wavelengths between 0.80 and 140 micron.
dc.descriptionAccepted for publication in A&A, 13 pages, 6 figures, 9 tables
dc.identifierhttps://arxiv.org/abs/astro-ph/0703145
dc.identifierhttp://arxiv.org/abs/astro-ph/0703145
dc.identifierAstron.Astrophys.467:753-760,2007
dc.identifierdoi:10.1051/0004-6361:20077108
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/175329
dc.subjectAstrophysics
dc.titleAccurate Ritz wavelengths of parity-forbidden [Fe II], [Ti II] and [Cr II] infrared lines of astrophysical interest
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