J/A+A/570/A12 Spectroscopy of 1,2-propanediol (Bossa+, 2014)
Laboratory spectroscopy of 1,2-propanediol at millimetre and submillimeter
wavelengths.
Bossa J.B., Ordu M.H., Muller H.S.P., Lewen F., Schlemmer S.
<Astron. Astrophys. 570, A12 (2014)>
=2014A&A...570A..12B 2014A&A...570A..12B
ADC_Keywords: Atomic physics
Keywords: molecular data - methods: laboratory: molecular -
techniques: spectroscopic - ISM: molecules
Abstract:
Ethandiol is among the largest complex organic molecules detected in
space thus far. It has been found in different types of molecular
clouds. The two propanediol isomers are the next larger diols.
Hence,they are viable candidates to be searched for in space. We want
to provide sufficiently large and accurate sets of spectroscopic
parameters of 1,2-propanediol to facilitate searches for this molecule
at millimeter and longer submillimeter wavelengths. We recorded
rotational spectra of 1,2-propanediol in three large frequency windows
between 38 and 400GHz. We made extensive assignments for the three
lowest energy conformers to yield spectroscopic parameters up to
eighth order. Our present data will be helpful for identifying
1,2-propanediol at moderate submillimeter or longer wavelengths with
radio telescope arrays such as ALMA, NOEMA, or EVLA. In particular,
its detection with ALMA in sources, in which ethanediol was detected,
appears to be promising.
Description:
Three conformers of 1,2-propanediol have been studied in this work,
aG'g, gG'a, and g'G'g.
1) The molecules are asymmetric top rotors. Watson's S-reduction was
used in the representation Ir. Data below 26GHz are from previous
work: Lovas et al., 2009 for all conformers; in the case of the aG'g
conformer (table3.dat), the first set of lines between 6 and 18GHz is
from Lockley et al., 2002, J. Mol. Struct., 612, 199.
All data above 38.5GHz are from this work.
The average frequency of blended lines (identical transition
frequencies for two or more transitions) is identical to the
intensity-weighted average. We therefore omitted the
intensity-weighting specified in the line file after the uncertainties
in SPFIT.
2) Internal coordinates are given in separate txt files.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 51 2013 Measured lines for the aG'g conformer
table5.dat 51 1401 Measured lines for the gG'a conformer
table6.dat 51 1198 Measured lines for the g'G'g conformer
g.txt 80 49 Internal coordinates for the aG'g conformer
a.txt 80 49 Internal coordinates for the gG'a conformer
g1.txt 80 49 Internal coordinates for the g'G'g conformer
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Description of file:
Each file *.txt consists of a title line, then lines 3-15 is the
z-matrix stating the first the atom plus (if applicable), next the
line to which the bond length B refers to and the label B with
numbering, next the line to which the bond angle A refers to and the
label A with numbering, next the line to which the dihedral (or
torsional) angle D refers to and the label D with numbering (lines 17
to 49 provide the values for B1 to B12 (in 100pm), A1 to A11, and D1
to D10 (in degrees)).
Byte-by-byte Description of file: table[456].dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- J" [1/71] Upper J quantum number
4- 5 I2 --- Ka" [0/45] Upper Ka quantum number
7- 8 I2 --- Kc" [0/71] Upper Kc quantum number
12- 13 I2 --- J' [0/71] Lower J quantum number
15- 16 I2 --- Ka' [0/45] Lower Ka quantum number
18- 19 I2 --- Kc' [0/70] Lower Kc quantum number
23- 34 F12.5 MHz Freq [6426/399264] Observed transition frequency
36- 40 F5.3 MHz e_Freq [0.002/0.09] Uncertainty of measurements
44- 51 F8.5 MHz O-C [-0.2/0.2] Observed-Calculated frequencies
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Acknowledgements:
Holger S.P. Mueller, hspm(at)ph1.uni-koeln.de
(End) Holger S.P. Mueller [Universitat zu Koeln], E. Perret [CDS] 22-Aug-2014