Relative O(3Pj = 2.1.0) spin-orbit populations correlated with specific NO[2ΠΩ = 1/2 , 3/2; ν = 0; f; Λ = Π(A′), Π(A″)] product states were obtained following photolysis of NO2 at excess energies E± = 390, 425, and 1054 cm-1. These fully quantum state-resolved measurements were carried out by recording spatial profiles of recoiling NO(2ΠΩ, J, Λ) products using polarized radiation for photolysis and state-selective laser ionization detection. The relative O(3Pj) populations correlated with each NO(2ΠΩ, J, Λ) state show marked fluctuations at each excess energy as a function of rotational state and Λ-doublet component. The relative populations also fluctuate as a function of excess energy. The O(3Pj) spin-orbit population ratios, when averaged over all measurements, exhibit distributions that are colder than statistical, in agreement with previous results. In particular, we find that, on average, O(3P1):O(3P2) population ratios correlated with the ground NO(2Π 1/2 ) state are colder than the corresponding ratios correlated with the excited NO(2Π3/2) spin-orbit state. These results are in agreement with the state-specific calculations of Katigiri and Kato [J. Chem. Phys. 1993, 99, 8805] and are discussed in terms of long-range nonadiabatic transitions among electronic states correlating asymptotically with different spin-orbit states of the ground NO(2Π) + O(3P) dissociation channel.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry