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Institut des Sciences Moléculaires d'Orsay


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jeudi 27 février


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mercredi 26 février


Accueil > Équipes scientifiques > Systèmes Moléculaires, Astrophysique et Environnement (SYSTEMAE) > Recherche > Thème 1 : Spectroscopie de molécules neutres, radicalaires et ioniques pour l’astrophysique > Spectroscopy in high finesse cavities

Spectroscopy in high finesse cavities

The aim of several members of the group is to obtain new spectroscopic information concerning neutral saturated molecules and neutral or ionic molecular radicals of astrophysical interest produced either within plasma generated by a radiofrequency (13.56 MHz ), microwave or electric discharge, or thanks to laser photolysis. Various spectroscopic data can be obtained such as : position of absorption bands, absorption cross sections, oscillator strengths, rotational constants, radical production efficiency, isotopic intensity ratios for very weak vibrational overtone absorption bands located in the near IR or in the visible, but also for weak forbidden or more intense allowed electronic transitions located in the visible or in the near UV range. The absolute and very sensitive absorption Cavity Ring-Down technique is used to reach this goal with a spectral resolution of about 0.2 cm-1 (corresponding to the typical resolution given by several pulsed nanosecond lasers). We have also developed recently a new apparatus coupling 2 cavities and the heterodyne technique allowing to perform absorption spectroscopy with a much better spectral resolution (possibly down to 10-5 cm-1, i.e. 300 kHz) than using our conventional light sources (nanoseconds pulsed lasers).