| Description |
We propose to perform a deep search for the CH2D+ ionwith Herschel/HIFI. This species plays a key role in interstellar chemistry, especially for deuterium fractionation at moderate temperature, but also as tracer of the symmetrical species CH3+.Because of its low dipole moment, and floppy character, its rotational transitions were not accurately known until recently (Amano 2010). Also, only two millimeter transition and onesubmillimeter transition are available from the ground, but inspectral regions where multiple emission lines from other speciesare present. Therefore, this ion escaped detection despite extensive searches bysome of the proponents for over 30 years. Three of the most intense linesof CH2D+ are accessible to Herschel/HIFI in relatively clean spectralregions. The detection of CH2D+ seems therefore to be finally withinreach, providing a key proof of the validity of state of the artchemical networks. |
