The millimeter-wave spectrum of the CaF radical (X 2+)

M. A. Anderson, M. D. Allen, L. M. Ziurys

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The pure rotational spectrum of the CaF radical has been measured in the laboratory using millimeter/sub-mm direct absorption specstroscopy. Fourteen rotational transitions have been detected originating in the v = 0 mode of the species. Rotational lines of the vibrationally excited v = 1, 2, and 3 states have also been observed. Spin-rotation splittings, as well as hyperfine interactions arising from the nuclear spin of the fluorine atom, were resolved in the CaF spectra. Rotational, fine-structure, and in some cases, hyperfine parameters were determined for the various vibrational modes of the molecule from a nonlinear least-squares fit to the data, using a 2∑ Hamiltonian, and are in agreement with past measurements. The newly measured rest frequencies for CaF, which are accurate to at least ± 100 kHz, will enable astronomical searches to be conducted for the molecule in interstellar and circumstellar gas. Given the recent detection of AlF in IRC + 10216, metal fluoride species may be more abundant than previously thought.

Original languageEnglish (US)
Pages (from-to)503-506
Number of pages4
JournalAstrophysical Journal
Issue number1
StatePublished - Mar 20 1994


  • ISM: molecules
  • Line: identification
  • Molecular data

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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