Branching ratios for infrared vibrational emission from NO(X2II, v'=2-13)

• Published in: The Journal of chemical physics 1992-05, Vol.96 (10), p.7555-7563
• Main Authors: RAWLINS, W. T, FRASER, M. E, MILLER, S. M, BLUMBERG, W. A. M
• Format: Article
• Language: English
• Subjects: Atomic and molecular physics; Exact sciences and technology; Intensities and shapes of molecular spectral lines and bands; Molecular properties and interactions with photons; Physics
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.462407

The ratios of overtone and fundamental vibrational Einstein coefficients for NO(X 2Π) have been measured by spectrally resolved infrared chemiluminescence near 2.7–3.3 μm and 5.2–6.8 μm. The reactions of N(2D,2P) with O2, in the presence of a small background of He in a cryogenic low-pressure reactor, generated vibrationally excited, rotationally cold (60 K) NO(v), whose emission spectra were recorded with high spectral resolution. Least-squares spectral fitting analysis of the observed overtone and fundamental spectra gave vibrational band intensities, whose ratios at each emitting vibrational level v′ yielded the (Δv=2)/(Δv=1) Einstein coefficient ratios for v′=2–13. The results provide comparisons to previous theoretical and experimental data, and reflect the behavior of the dipole moment function for NO(X 2Π). The measured ratios indicate an overtone Einstein coefficient A2,0=0.94±0.11 s−1 for an assumed fundamental value A1,0=13.4 s−1.