Detection of the quadrupole hyperfine structure in HCNH

Lucy M Ziurys, A. J. Apponi, J. T. Yoder

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

We report the first measurement of the electric quadrupole hyperfine structure of HCNH+ . The J = 1 → 0 transition of this interstellar molecular ion was observed toward the cold, dark cloud TMC-1, using the NRAO 12m telescope at 74 GHz. The three hyperfine components of this transition were clearly detected and resolved, enabling the first experimental determination of the quadrupole coupling constant eqQ of HCNH+. The value of this constant is calculated to be eqQ = -0.49 ± 0.07 MHz. The column density of HCNH+ toward TMC-1 was found to be Ntot, ∼ 2.8 × 1013 cm-2, corresponding to a fractional abundance relative to H2 of f ∼ 3 × 10-9. This abundance is at least one order of magnitude higher than the predictions of ionmolecule chemistry. Detection of the hyperfine structure clearly establishes the presence of HCNH+ in interstellar space.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume397
Issue number2 PART 2
StatePublished - Oct 1 1992
Externally publishedYes

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hyperfine structure
relative abundance
quadrupoles
interstellar space
ion
prediction
molecular ions
telescopes
chemistry
predictions
detection
cold

Keywords

  • ISM: abundances
  • ISM: molecules
  • Line: identification
  • Radio lines: molecular: interstellar

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Detection of the quadrupole hyperfine structure in HCNH. / Ziurys, Lucy M; Apponi, A. J.; Yoder, J. T.

In: Astrophysical Journal, Vol. 397, No. 2 PART 2, 01.10.1992.

Research output: Contribution to journalArticle

Ziurys, LM, Apponi, AJ & Yoder, JT 1992, 'Detection of the quadrupole hyperfine structure in HCNH', Astrophysical Journal, vol. 397, no. 2 PART 2.
Ziurys, Lucy M ; Apponi, A. J. ; Yoder, J. T. / Detection of the quadrupole hyperfine structure in HCNH. In: Astrophysical Journal. 1992 ; Vol. 397, No. 2 PART 2.
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N2 - We report the first measurement of the electric quadrupole hyperfine structure of HCNH+ . The J = 1 → 0 transition of this interstellar molecular ion was observed toward the cold, dark cloud TMC-1, using the NRAO 12m telescope at 74 GHz. The three hyperfine components of this transition were clearly detected and resolved, enabling the first experimental determination of the quadrupole coupling constant eqQ of HCNH+. The value of this constant is calculated to be eqQ = -0.49 ± 0.07 MHz. The column density of HCNH+ toward TMC-1 was found to be Ntot, ∼ 2.8 × 1013 cm-2, corresponding to a fractional abundance relative to H2 of f ∼ 3 × 10-9. This abundance is at least one order of magnitude higher than the predictions of ionmolecule chemistry. Detection of the hyperfine structure clearly establishes the presence of HCNH+ in interstellar space.

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