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J/A+A/615/A140        C4H9CN anti and gauche conformer data      (Wehres+, 2018)

Rotational spectroscopy of the two conformers of 3 methylbutyronitrile (C4H9CN) between 2 and 400 GHz. Wehres N., Wilkins O.H., Borisov K., Lewen F., Grabow J.-U., Schlemmer S., Mueller H.S.P. <Astron. Astrophys. 615, A140 (2018)> =2018A&A...615A.140W (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics Keywords: laboratory: molecular - techniques: spectroscopic - radio lines: ISM - ISM: molecules - astrochemistry Abstract: We present high-resolution rotational spectroscopy of the two conformers of 3-methylbutyronitrile (C4H9CN). Spectra were taken between 2 and 24GHz by means of Fourier transform microwave spectroscopy. Spectra between 36 and 403 GHz were recorded by means of frequency modulated (FM) absorption spectroscopy. The analysis yields precise rotational constants and higher order distortion constants, as well as a set of 14N nuclear electric quadrupole coupling parameters for each of the two conformers. In addition, quantum chemical calculations were performed in order to assist the assignments. Frequency calculations yield insight into the vibrational energy structure of the two conformers, from which partition functions and vibrational correction factors are determined. These factors are used to determine experimentally and computationally the energy difference between the two conformers, which is revealed to be negligible. Overall, this study provides precise spectroscopic constants for the search of 3-methylbutyronitrile in the interstellar medium. In particular, this molecule is a perfect test case for our knowledge of branched molecule formation in space. Description: fits output files: The files contain the fit files from SPFIT for 3-methylbutyronitrile, anti and gauche conformer. The quantum numbers are labelled as: J', K_a', K_c', 0/1, F', J", K_a", K_c", 0/1, F where 0 indicates hyperfine splitting is (partially) resolved, and 1 is without hyperfine splitting being resolved. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file 3MBN-anti-conformer-fit.txt 135 6714 3-methylbutyronitrile anti conformer SPFIT data 3MBN-gauche-conformer-fit.txt 135 5383 3-methylbutyronitrile gauche conformer SPFIT data
Acknowledgements: Nadine Wheres, wehres(at)
(End) Patricia Vannier [CDS] 13-Jun-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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