Transition probabilities and electronic transition moments of the A~2#SIGMA#~+ - X~2#PI# and D~2#SIGMA#~+ - X~2#PI# systems of nitric oxide

摘要

Dispersed fluorescence scans of the A - X(4,v") and D - X(0,v") progressions of nitric oxide, after two-photon excitation, are used to determine the electronic transition moments of these band systems. The measured collision free lifetimes of 206 +- 7 ns for A ~2#SIGMA#~+, v' = 0, and 18 +- 1 ns for D ~2#SIGMA#~+, v' = 0 are used to place transition probabilities on an absolute basis. The branching ratio for D -> X is 3.0 +- 0.3 times that for D -> A and more than 30 times that for D -> C. The ratio of two-photon absorption cross sections for D-X (0,0)/A - X(4,0) is 6 +- 2 and the photoionization probability from D, v' = 0 is larger than from A, v' = 4 at 375 nm. Also, the two-photon excitation of A - X(4,0) has an unusual intensity distribution, probably due either to interference between intermediate states in the excitation or to anomalies in the photoionization step.