The NO(a 4Π) state: first gas phase kinetic measurements

Observation of the temporal evolution of NO(a 2Π−X 2Π) emission following one-photon excitation of the NO(a 4Π) state is used to study NO(a) kinetics. Loss rate coefficients are determined for the v = 11 level, using NO and He as colliders. The loss rate coefficient for NO is (1.44 ± 0.29) × 10−10 cm3 s−1, and that for He is (1.23 ± 0.16) × 10−12 cm3 s−1; comparisons are made with the approximately isoenergetic v = 2 level of the B 2Π state. Details of the a → B electronic energy transfer process are investigated. Transfer to the nearest B 2Π level, v = 2, occurs relatively rapidly, whereas population of the v = 0 level requires vibrational cascading within the quartets.