Vuv photolysis of hydrazoic acid: Absorption and fluorescence excitation spectra

• Published in: The Journal of chemical physics 1998-08, Vol.109 (6), p.2210-2219
• Main Authors: Schönnenbeck, G., Biehl, H., Stuhl, F., Meier, U., Staemmler, V.
• Format: Article
• Language: English
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.476789

The vuv-absorption of the HN3/DN3 isotopomers and the formation of NH/ND photofragments in the (c 1Π) and (A 3Π) states were studied. Tunable synchrotron radiation and several atomic resonance lines were used as light sources. The absorption spectrum, which shows more features than reported earlier, was analyzed by means of extensive quantum chemical ab initio calculations. The internal energies of the observed NH/ND(c,A) photofragments were estimated as a function of the photolysis wavelength by emission spectroscopy. The fragment NH/ND(c) is formed with a rather constant quantum yield below 147 nm, while the relative production yield of NH/ND(A) increases with decreasing wavelength. Although NH/ND(A) can be formed directly via a spin forbidden process at long wavelengths, it is more efficiently produced by reactions of the three different triplet N2(A,B,B′) states with HN3/DN3. The variation of the vibrational distribution of the NH/ND(A) radicals indicates that various production mechanisms exist.