VUV PHOTOLYSIS OF HYDRAZOIC ACID - ABSORPTION AND FLUORESCENCE EXCITATION-SPECTRA

The vuv-absorption of the HN3/DN3 isotopomers and the formation of NW/ ND photofragments in the (ce (II)-I-1) and (A (II)-I-3) states were st udied. Tunable synchrotron radiation and several atomic resonance line s were used as light sources. The absorption spectrum, which shows mor e features than reported earlier, was analyzed by means of extensive q uantum chemical ab initio calculations. The internal energies of the o bserved NWND(c,A) photofragments were estimated as a function of the p hotolysis wavelength by emission spectroscopy. The fragment NWND(c) is formed with a rather constant quantum yield below 147 nm, while the r elative production yield of NWND(A) increases with decreasing waveleng th. Although NWND(A) can be formed directly via a spin forbidden proce ss at long wavelengths, it is more efficiently produced by reactions o f the three different triplet N-2(A,B,B') states with HN3/DN3. The var iation of the vibrational distribution of the NH/ND(A) radicals indica tes that various production mechanisms exist. (C) 1998 American Instit ute of Physics.