Total and state-to-state rate coefficients for rotational energy transfer in collisions between NO(Chi(2)Pi) and He at temperatures down to 15 K

Infrared-ultraviolet double resonance (IRUVDR) experiments have been implemented in the ultra-cold environment provided by a CRESU (Cinetique de Reaction en Ecoulement Supersonique Uniforme) apparatus. This has enabled us to measure rate coefficients for rotational energy transfer in collisions between NO and He of two kinds: those relating to total removal from a specific rovibrational state of NO(X (2) Pi; Omega = 1/2; upsilon = 3; J = 0.5, 3.5 or 6.5) and also state-to-state rate coefficients for transfer from these levels. Using different Laval nozzles, results have been obtained at four different temperatures: 149, 63, 27 and 15 K, and are also reported for 795 K. (C) 1997 Elsevier Science B.V.