The FERRUM project: metastable lifetimes in Cr II
Backstrom, E.; Gurell, J.; Royen, P.; Mannervik, S., et al. (2012). The FERRUM project: metastable lifetimes in Cr II. Monthly Notices of the Royal Astronomical Society, 420, (2), 1636 - 1639
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Published
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English
Authors:
Backstrom, E.
;
Gurell, J.
;
Royen, P.
;
Mannervik, S.
, et al.
Department:
Lund Observatory - Has been reorganised
Abstract:
Parity forbidden radiative transitions from metastable levels are observed in spectra of low-density astrophysical plasmas. These lines are used as probes of the physical conditions, made possible due to the long lifetime of their upper level. In a joint effort, the FERRUM project aims to obtain new and accurate atomic data for the iron-group elements, and part of this project concerns forbidden lines. The radiative lifetimes of the metastable energy levels 3 d4(a 3 D)4 s c4 D 5/2 and 3 d4(a 3 D)4 s c4 D 7/2 of singly ionized chromium have been measured. The experiment has been performed at the ion storage ring CRYRING. We employed a laser-probing technique developed for measuring long lifetimes. In this article, we present the lifetimes of these levels to be t5/2= 1.28(16) s and t7/2= 1.37(7) s, respectively. A comparison with previous theoretical work shows good agreement and the result is discussed in a theoretical context.
Keywords:
atomic data ;
methods: laboratory ;
techniques: spectroscopic ;
astronomical data bases: miscellaneous
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