Observation of collision induced state-to-state energy transfer in electronically and highly rotationally excited NH2

Abstract

State-to-state energy transfer of NH2 in its excited state à 2A1 is investigated with time-resolved Fourier transform emission spectroscopy. Originating from collisions with NH3, rovibrational energy transfer in NH2(à 2A1) with energy separations |ΔE|<260 cm−1 and in multiples of ΔE≈−1050 cm−1 is observed. Based on the experimental determination of relative transition probabilities, absolute state-to-state rate constants are derived. Collisional changes in the rotational quantum number range from −3 to +4. The analysis of the time dependence of the levels populated by rovibrational energy transfer shows that this variety is not the result of secondary collisions.