Rotational rest frequencies for FeN (X 2Δi) and revised spectroscopic constants for FeC (X 3Δi)

P. M. Sheridan, L. M. Ziurys, T. Hirano

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The pure rotational spectrum of FeN in its X 2Δ i, ground state has been recorded using millimeter-wave direct absorption techniques in the range 198-525 GHz. New measurements have also been carried out for FeC (X3ΔI), in particular of the Ω = 1 fine-structure component and the 54FeC isotopomer. These molecules were created by the reaction of iron vapor with either CH4 (FeC) or N2 (FeN) in a DC discharge. Eight rotational transitions were recorded for FeN in its lowest-lying spin component, Ω = 5/2, and multiple transitions were measured for FeC in all three of its spin-orbit ladders, as well as for 54FeC (Ω = 3). These data have been analyzed, and precise spectroscopic constants for both radicals have been determined. The fine structure in FeC was found to exhibit an irregular pattern, indicating that higher order spin-orbit perturbations are occurring in this molecule. Although only one spin component was observed for FeN, the bond length established from the Ω = 5/2 data is consistent with a 2Δ ground state, as indicated by theory. Fe-bearing species are relevant to many astrophysical topics, including astrochemistry, dust grains composition, nucleosynthesis, and mass loss from asymptotic giant branch stars.

Original languageEnglish (US)
Pages (from-to)L141-L144
JournalAstrophysical Journal
Issue number2 II
StatePublished - Aug 20 2003


  • Astrochemistry
  • ISM: molecules
  • Line: identification
  • Methods: laboratory molecular data
  • Stars: AGB and post-AGB

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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