J/A+A/623/A167 C2H3SH observed experimental transitions (Martin-Drumel+, 2019)
Submillimeter spectroscopy and astronomical searches of vinyl mercaptan,
C2H3SH.
Martin-Drumel M.-A., Lee K.L.K., Belloche A., Zingsheim O., Thorwirth S.,
Mueller H.S.P., Lewen F., Garrod R.T., Menten K.M., McCarthy M.C.,
Schlemmer S.
<Astron. Astrophys. 623, A167 (2019)>
=2019A&A...623A.167M 2019A&A...623A.167M (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Interstellar medium
Keywords: astrochemistry - molecular data - method: laboratory: molecular -
ISM: individual objects: Sagittarius B2 (N) - ISM: molecules -
surveys
Abstract:
New laboratory investigations of the rotational spectrum of postulated
astronomical species are essential to support the assignment and
analysis of current astronomical surveys. In particular, considerable
interest surrounds sulfur analogs of oxygen-containing interstellar
molecules and their isomers.
To enable reliable interstellar searches of vinyl mercaptan, the
sulfur-containing analog to the astronomical species vinyl alcohol, we
investigated its pure rotational spectrum at millimeter wavelengths.
We extended the pure rotational investigation of the two isomers syn
and anti vinyl mercaptan to the millimeter domain using a
frequency-multiplication spectrometer. The species were produced by a
radiofrequency discharge in 1,2-ethanedithiol. Additional transitions
were remeasured in the centimeter band using Fourier-transform
microwave spectroscopy to better determine rest frequencies of
transitions with low-J and low-Ka values. Experimental investigations
were supported by quantum chemical calculations on the energetics of
both the [C2,H4,S] and [C2,H4,O] isomeric families.
Interstellar searches for both syn and anti vinyl mercaptan as well as
vinyl alcohol were performed in the EMoCA spectral line survey carried
out toward Sgr B2(N2) with ALMA. Results. Highly accurate experimental
frequencies (to better than 100kHz accuracy) for both syn and anti
isomers of vinyl mercaptan are measured up to 250GHz; these deviate
considerably from predictions based on extrapolation of previous
microwave measurements. Reliable frequency predictions of the
astronomically most interesting millimeter-wave lines for these two
species can now be derived from the best-fit spectroscopic constants.
From the energetic investigations, the four lowest singlet isomers of
the [C2,H4,S] family are calculated to be nearly isoenergetic, which
makes this family a fairly unique test bed for assessing possible
reaction pathways. Upper limits for the column density of syn and anti
vinyl mercaptan are derived toward the extremely molecule-rich
star-forming region Sgr B2(N2) enabling comparison with selected
complex organic molecules.
Description:
The tables constain the list of measured transitions of both syn- and
anti-vinyl mercaptan. Frequencies are given in MHz. Values in
parentheses represent 1sigma uncertainty. The obs.-calc. values are
given in kHz.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tableb1.dat 41 296 Observed experimental transitions of vinyl mercaptan
tableb2.dat 41 173 Observed frequencies for anti-vinyl mercaptan
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb1.dat tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- J' Lower J quantum number
4- 5 I2 --- Ka' Lower Ka quantum number
7- 8 I2 --- Kc' Lower Kc quantum number
10- 11 I2 --- J" Upper J quantum number
13- 14 I2 --- Ka" Upper Ka quantum number
16- 17 I2 --- Kc" Upper Kc quantum number
19- 29 F11.4 MHz Obs Observed transition frequency
31- 34 I4 10-4MHz e_Obs 1σ error on Obs
36- 41 F6.1 MHz O-C Observed minus calculated frequencies
--------------------------------------------------------------------------------
Acknowledgements:
Marie-Aline Martin-Drumel, marie-aline.martin(at)u-psud.fr
(End) Patricia Vannier [CDS] 28-Feb-2019