Abstract
Rotationally resolved emission of NO, produced from photolysis of HNO 3 at 193 nm, in the near infrared region (8900-9300 cm -1 ) was recorded with a step-scan Fourier-transform interferometer at a resolution of 0.1 cm -1 . The emission is assigned as NO D 2 Σ-A 2 Σ + (v′ ,v″) = (0,0) band with rotational states N′=17-42. Emission from selective rotational states of NO D 2 Σ + was observed when HNO 3 was photolyzed with an ArF excimer laser having a narrow bandwidth ≈0.01 nm. The experimental results indicate that the D 2 Σ + state of NO is formed via absorption of another 193 nm photon by NO (v″=1) in the ground electronic state. The measured distribution of intensity implies that NO is produced highly rotationally excited; the most likely mechanism for formation of NO is from the unstable NO 2 fragment undergoing secondary dissociation. © 1995 American Institute of Physics.