Experimental energy levels and partition function of the 12C2 molecule

T. Furtenbacher, István Szabó, A. Császár, Peter F. Bernath, Sergei N. Yurchenko, Jonathan Tennyson

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The carbon dimer, the 12C2 molecule, is ubiquitous in astronomical environments. Experimental-quality rovibronic energy levels are reported for 12C2, based on rovibronic transitions measured for and among its singlet, triplet, and quintet electronic states, reported in 42 publications. The determination utilizes the Measured Active Rotational-Vibrational Energy Levels (MARVEL) technique. The 23,343 transitions measured experimentally and validated within this study determine 5699 rovibronic energy levels, 1325, 4309, and 65 levels for the singlet, triplet, and quintet states investigated, respectively. The MARVEL analysis provides rovibronic energies for six singlet, six triplet, and two quintet electronic states. For example, the lowest measurable energy level of the state, corresponding to the J = 2 total angular momentum quantum number and the F 1 spin-multiplet component, is 603.817(5) cm-1. This well-determined energy difference should facilitate observations of singlet-triplet intercombination lines, which are thought to occur in the interstellar medium and comets. The large number of highly accurate and clearly labeled transitions that can be derived by combining MARVEL energy levels with computed temperature-dependent intensities should help a number of astrophysical observations as well as corresponding laboratory measurements. The experimental rovibronic energy levels, augmented, where needed, with ab initio variational ones based on empirically adjusted and spin-orbit coupled potential energy curves obtained using the Duo code, are used to obtain a highly accurate partition function, and related thermodynamic data, for 12C2 up to 4000 K.

Original languageEnglish
Article number44
JournalAstrophysical Journal, Supplement Series
Volume224
Issue number2
DOIs
Publication statusPublished - Jun 1 2016

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partitions
energy levels
energy
molecules
comets
electronics
atomic energy levels
quantum numbers
astrophysics
potential energy
angular momentum
fine structure
comet
dimers
orbits
thermodynamics
carbon
curves

Keywords

  • molecular data

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Experimental energy levels and partition function of the 12C2 molecule. / Furtenbacher, T.; Szabó, István; Császár, A.; Bernath, Peter F.; Yurchenko, Sergei N.; Tennyson, Jonathan.

In: Astrophysical Journal, Supplement Series, Vol. 224, No. 2, 44, 01.06.2016.

Research output: Contribution to journalArticle

Furtenbacher, T. ; Szabó, István ; Császár, A. ; Bernath, Peter F. ; Yurchenko, Sergei N. ; Tennyson, Jonathan. / Experimental energy levels and partition function of the 12C2 molecule. In: Astrophysical Journal, Supplement Series. 2016 ; Vol. 224, No. 2.
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