|dc.identifier.citation||Carvajal Zaera, M., Margulès, L., Tercero, B., Demyk, K.,Kleiner, I., Guillemin, J. C., Lattanzi, V., Walters, A., Demaison, J., Wlodarczak, G., Huet, T. R., Ilyushin, V. V., Møllendal, H., Cernicharo, J.: "Rotational spectrum of 13C2-methyl formate (HCOO13CH3) and detection of the two 13C-methyl formate in Orion". Astronomy and Astrophysics. Vol. 500, n. 3, p. 1109-1118 (2009). ISSN 0004-6361||en_US
|dc.description.abstract||Laboratory measurements and analysis of the microwave and millimeter-wave spectra of potential interstellar molecules
are a prerequisite for their subsequent identification by radioastronomical techniques. The spectral analysis provides spectroscopic
parameters that are used in the assignment procedure of the laboratory spectra, and that also predict the frequencies of transitions not
measured in the laboratory with a high degree of precision.
Aims. An experimental laboratory study and its theoretical analysis is presented for 13C2-methyl formate (HCOO13CH3) allowing a
search for this isotopologue in the Orion molecular cloud. The 13C1-methyl formate (H13COOCH3) molecule was also searched for
in this interstellar cloud, using previously published spectroscopic data.
Methods. The experimental spectra of 13C2-methyl formate were recorded in the microwave and sub-mm energy ranges (4–20 GHz,
8–80 GHz, 150–700 GHz). The spectra were analyzed using the Rho-Axis Method (RAM), which takes the CH3 internal rotation and
the coupling between internal rotation and global rotation into account.
Results. Twenty-seven spectroscopic constants of 13C2-methyl formate have been obtained from a fit of 936 transitions of the ground
torsional state with a standard (unitless) deviation of 1.08. A prediction of line positions and intensities is also produced. This prediction
allowed us to identify 230 13C2-methyl formate lines in the Orion interstellar molecular cloud.We refitted all previously published
ground state transitions of the 13C1-methyl formate molecule in order to provide a prediction of its ground state spectrum. 234 lines
of 13C1-methyl formate were detected in the Orion interstellar cloud using that prediction.||en_US