MOLECULAR UNIVERSE

The laboratory spectroscopy groups (Unibas, LILLE, CNRS, Cologne) have spectrometers of high spectral accuracy and sensitivity, covering most of the significant spectral range. The groups have complementary facilities and techniques of producing, characterizing and identifying astrophysical molecules by means of laboratory spectroscopy. The spectrometers of the LILLE group will study the millimeter and sub-millimeter range of small (deuterated) species in the ground and vibrationally excited states and of larger species in their low-lying ro-vibrational spectra. A new experimental set-up will include a laser desorption device. In order to select the best candidates, the same spectra are first investigated by FIR Fourier transform spectroscopy in CNRS at low resolution. High resolution (up to 0.002 cm^-1) thermal emission spectra of astrophysically relevant molecules (e.g. H₂O, NH₃, HCN) have also been recorded using a Fourier transform spectrometer with 4K bolometers in the far-IR (40-500 cm^-1) by the CNRS team. This technique will be extended by using more energetic sources towards the study of rotational emission spectra of free radical (OH, NH, NH₂). In addition, this spectrometer can be adapted to the synchrotron beams available at CNRS for sensitive absorption spectroscopy. CNRS will develop new techniques to optimize the concentration of transient species, before recording their spectra in the far-IR or sub-millimeter in the collaborating laboratories of the consortium. The Unibas group will measure the electronic spectra of astrophysically relevant molecules, radicals and ions, in particular carbon chains and their ions. Ultra high-resolution spectroscopy at Cologne focuses on stable and reactive species such as CO and its isotopomeres, light hydrides (e.g. SH, NH, PH, CH), large polyatomic molecules (HCN, HC_nN, n=3 … 7), radicals and ions (CO⁺, SO⁺, SH⁺) in the frequency range from 50 GHz up to 2 THz. The line position can be determined in best cases with a precision of 500 Hz by using the sub-Doppler mode of the spectrometer. Pure carbon chain molecules (e.g. C₈, C₁₀) can be produced with a UV-excimer laser ablation source. Rotationally resolved spectra of vibrational modes can be studied in all detail, after they have been characterized by matrix isolated spectra, obtained by the Unibas group. The broad experience of KUN in high resolution molecular spectroscopy will be applied to the analysis and interpretation of spectra from both small and large molecules.