Collisional Energy Transfer of NO D 2Σ+ (v‘ = 0) and A 2Σ+ (v‘ = 4) by O2, N2, Ar, and NO

Temporally and spectrally resolved fluorescence from NO D 2 Σ + v ‘ = 0 and A 2 Σ + v‘ = 4 after two-photon excitation is studied in the presence of O 2, N 2, Ar, and NO colliders at room temperature. Quenching rate constants are determined for these gases. Nitrogen is found to efficiently quench these levels, with rate constants of (2.6 ± 0.2) × 10 -10 cm 3 s -1 and (2 ± 0.15) × 10 -11 cm 3 s -1, respectively. The large quenching rate for A 2 Σ + v ‘ = 4 by N 2 compared to those of lower vibrational levels is explained by the onset of near resonant energy transfer into the N 2 A 3 Σ u + metastable state, similar to the path known for quenching the C 2 Π and D 2 Σ + states.