The hyperfine structure in the rotational spectrum of CF+

Abstract

Context. CF+ has recently been detected in the Horsehead and Orion Bar photo-dissociation regions. The J=1-0 line in the Horsehead is double-peaked in contrast to other millimeter lines. The origin of this double-peak profile may be kinematic or spectroscopic. Aims. We investigate the effect of hyperfine interactions due to the fluorine nucleus in CF+ on the rotational transitions. Methods. We compute the fluorine spin rotation constant of CF+ using high-level quantum chemical methods and determine the relative positions and intensities of each hyperfine component. This information is used to fit the theoretical hyperfine components to the observed CF+ line profiles, thereby employing the hyperfine fitting method in GILDAS. Results. The fluorine spin rotation constant of CF+ is 229.2 kHz. This way, the double-peaked CF+ line profiles are well fitted by the hyperfine components predicted by the calculations. The unusually large hyperfine splitting of the CF+ line therefore explains the shape of the lines detected in the Horsehead nebula, without invoking intricate kinematics in the UV-illuminated gas.

2 pages, 1 figure, Accepted for publication in A&A

References in corpus (2)

• Discovery of Interstellar CF+
• The IRAM-30m line survey of the Horsehead PDR: I. CF+ as a tracer of C+ and a measure of the Fluorine abundance

Cited by in corpus (12)

• The IRAM-30m line survey of the Horsehead PDR: II. First detection of the l-C3H+ hydrocarbon cation
• The IRAM-30m line survey of the Horsehead PDR: III. High abundance of complex (iso-)nitrile molecules in UV-illuminated gas
• Chemical complexity in the Horsehead photodissociation region
• Gas phase Elemental abundances in Molecular cloudS (GEMS). IV. Observational results and statistical trends
• HCO, c-C3H and CF+ : three new molecules in diffuse, translucent and "spiral-arm'' clouds
• Herschel/HIFI Spectral Mapping of C${}^{+}$, CH${}^{+}$, and CH in Orion BN/KL: The Prevailing Role of Ultraviolet Irradiation in CH${}^{+}$ Formation
• Detection of extragalactic CF+ toward PKS1830-211 -- Chemical differentiation in the absorbing gas
• Anomalous HCN emission from warm giant molecular clouds
• Laboratory rotational ground state transitions of NH${}_3$D${}^{+}$ and CF${}^{+}$
• Widespread Galactic CF+ absorption: detection toward W49 with the Plateau de Bure Interferometer
• CF${}^{+}$ excitation in the interstellar medium
• First detection of CF${}^{+}$ in the Large Magellanic Cloud