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Spectroscopic Constants and Vibrational Frequencies for l-C3H+ and Isotopologues from Highly-Accurate Quartic Force Fields: The Detection of l-C3H+ in the Horsehead Nebula PDR Questioned
- Publication Year :
- 2013
- Publisher :
- United States: NASA Center for Aerospace Information (CASI), 2013.
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Abstract
- Very recently, molecular rotational transitions observed in the photon-dominated region of the Horsehead nebula have been attributed to l-C3H+. In an effort to corroborate this finding, we employed state-of-the art and proven high-accuracy quantum chemical techniques to compute spectroscopic constants for this cation and its isotopologues. Even though the B rotational constant from the fit of the observed spectrum and our computations agree to within 20 MHz, a typical level of accuracy, the D rotational constant differs by more than 40%, while the H rotational constant differs by three orders of magnitude. With the likely errors in the rotational transition energies resulting from this difference in D on the order of 1 MHz for the lowest observed transition (J = 4 yields 3) and growing as J increases, the assignment of the observed rotational lines from the Horsehead nebula to l-C3H+ is questionable.
- Subjects :
- Astrophysics
Subjects
Details
- Language :
- English
- Database :
- NASA Technical Reports
- Notes :
- NNX12AG96A, , WBS 811073, , NNH06CC03B, , NNH10ZDA001N
- Publication Type :
- Report
- Accession number :
- edsnas.20140011646
- Document Type :
- Report