Submillimeter-Wave Rotational Spectroscopy of H_2F^+
Abstract
Five pure rotational transitions of H_2F^+ were observed in the 473-774 GHz range with a backward-wave oscillator based submillimeter-wave spectrometer. The H_2F^+ ion was generated in an extended negative glow discharge in a gas mixture of hydrogen fluoride generated by heating potassium hydrogen fluoride (HF_2K) granular powder at 150°C-160°C and hydrogen in an argon buffer. A simultaneous analysis of the rotational lines with 120 combination differences for the ground state derived from the infrared spectra obtained by Schäfer and Saykallyaand Fujimori et al. was carried out to determine the precise molecular constants for the ground state. The rotational transition frequencies that lie below 2 THz were calculated, together with their estimated uncertainties, to facilitate future astronomical identifications. Recently H_2Cl^+ was detected in NGC 6334I and Sgr B2 with the Heterodyne Instrument for Far-Infrared (HIFI) on board the Herschel Space Observatory, and HF was also detected in a wide variety of interstellar clouds with the same facility. The proton affinity of HF is smaller than those of N_2 and CO, so the abundance of H_2F^+ is likely to be low in dense molecular clouds. We will discuss abundances of H_2F^+ in diffuse molecular clouds, considering various chemical reaction rates.
T. Amano and T. Hirao, J. Mol. Spectrosc., 233, 7 (2005) E. Schäfer and R. J. Saykally, J. Chem. Phys., 81, 4189 (1984) R. Fujimori, Y. Hirata, K. Kawaguchi, and I. Morino, RE02, The 65Th OSU International Symposium on Molecular Spectroscopy (2010)(Columbus, OH) D. C. Lis et al., Astron. Astrophys., 521, L9 (2010) D. A. Neufeld et al., Astron. Astrophys., 518, L108 (2010) T. G. Phillips et al., Astron. Astrophys., 518, L109 (2010) P. Sonnentrucker et al., Astronon. Astrophys., 521, L12 (2010)- Publication:
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66th International Symposium On Molecular Spectroscopy
- Pub Date:
- June 2011
- Bibcode:
- 2011mss..confETF05F
- Keywords:
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- ASTRONOMICAL SPECIES AND PROCESSES