EXCITATION OF HNO BY O2(1-DELTA-G)

Chemiluminescence spectra of HNO(1A″ → 1A′) sensitized by O2(1Δg) were obtained in reaction systems H-NO-O2(1Δg)/O2 (I) and O-C2H4-NO-O2(1Δ g)/O2 (II). In reaction system I, results show that excited HNO(1A″) was produced by O2(1Δg) sensitized excitation of the triplet state of HNO, HNO(3A″) + O2(1Δg) → HNO(1A″) + O2(3Σg-), through the formation of HNO(3A″) by (A) H + NO + M → HNO(1A′) + M; HNO(1A′) + O2(1Δg) → HNO(3A″) + O2(3Σg-), and (B) H + NO + M → HNO(3A″) + M. Experimental observations in reaction system II are consistent with the pumping scheme HNO(1A′) + O2(1Δg) → HNO(3A″) + O2(3Σg-); HNO(3A″) + O2(1Δg) → HNO(1A″) + O2(3Σg-). The excitation mechanism of HNO by the interaction of the HNO triplet state (3A″) with O2(1Δg) can illustrate the characteristic vibronic distribution in the 1A″ state. The excitation energy of HNO(3A″) is predicted to be 19.5 kcal mol-1. © 1978 American Chemical Society.