Accueil > Équipes scientifiques > Systèmes Moléculaires, Astrophysique et Environnement (SYSTEMAE) > Recherche > Thème 1 : Spectroscopie de molécules neutres, radicalaires et ioniques pour l’astrophysique > Rotational spectroscopy from the sub-mm to the THz range
Rotational spectroscopy from the sub-mm to the THz range
The advent of new generation observational platforms as the Atacama Large Millimeter Array (ALMA) and the NOrthern Extended Millimeter Array (NOEMA), that allows observation of various astrophysical objects in the millimeter and submillimeter wavelengths (roughly 50 GHz -1 THz), strengthen the need for laboratory data in this spectral range for molecules of astrophysical interest.
To enable new interstellar detections, our groups investigate in the laboratory the rotational spectrum of molecules, both stable and reactive (produced by radiofrequency, microwave, electrical discharges or H abstraction by F atoms), in this spectral region where the observed transitions act as unique fingerprints. We use a submillimeter spectrometer allowing to cover the 75-900 GHz region using electronic sources (frequency multiplication chain) and are developing a broadband (chirped-pulse) spectrometer in the 75-110 GHz region.
Theoretical treatments are also developed to deal with non-rigid molecules for which the harmonic or rigid-rotator approximations are not valid. For instance, a large number of astrophysically relevant molecules display internal rotation of a symmetrical, CH3 or CD3, or an asymmetrical, CH2D or CD2H, methyl group. These theoretical treatment are necessary to carry out the line position and line intensity analysis of their spectrum.