Products of the quenching of NO A 2Σ+ (v = 0) by N2O and CO2

• Published in: Physical chemistry chemical physics : PCCP Vol. 15; no. 7; pp. 2554 - 2564
• Main Authors: Burgos Paci, Maximiliano A, Few, Julian, Gowrie, Sarah, Hancock, Gus
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.02.2013
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Nitrogen oxide; Nitrogen protoxide
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c2cp43878j

Collisional quenching of NO A 2 Σ + ( v = 0) by N 2 O and CO 2 has been studied through measurements of vibrationally excited products by time resolved Fourier transform infrared emission. In both cases vibrationally excited NO X 2 Π ( v ) is seen and quantified in levels v ≥ 2 with distributions which are close to statistical. However the quantum yields to produce these levels are markedly different for the two quenchers. For CO 2 such quenching accounts for only ca. 26% of the total: for N 2 O it is ca. 85%. Far more energy is seen in the internal modes of the CO 2 product than those of N 2 O. The results are rationalised in terms of cleavage of the N 2 -O bond being dominant in the latter case, with either a similar O atom production or a specific channel producing almost exclusively NO in low vibrational levels ( v = 0,1) for quenching by CO 2 . Minor reactive channels yielding NO 2 are seen in both cases, and O( 1 D) is observed with low quantum yield in the reaction with N 2 O. The results are discussed in terms of previous models of the quenching processes, and are consistent with the very high yield of NO X 2 Π ( v = 0) previously observed by laser induced fluorescence for quenching of NO A 2 Σ + ( v = 0) by CO 2 . Products of the quenching of NO A 2 Σ + ( v = 0) by N 2 O and CO 2 are observed by time resolved FTIR emission. Vibrationally excited ground electronic states of NO, CO 2 and N 2 O are seen, and reactive channels are identified.