Knowledge Bank

Ammonia can be regarded as a unique model system for the investigation of collisional energy transfer processes of polar symmetric top molecules. State resolved R-R and R-T energy transfer of vibrationally excited $NH3(v2=1$) in collisions with $NH3$ and Ar has been measured in IR-double-resonance experiments with a tunable diode laser. A master equation analysis was used to convert the state resolved experimental data into average microscopic” state-to-state cross sections. In the present contribution the detailed set of state resolved rotational energy transfer data will be analysed with respect to theoretical scaling laws for individual state-to-state coefficients, propensity rules” for rotational energy transfer of polar molecules and intermolecular potential surface parameters of the two collision partners.