Nascent rotational and vibrational state distributions of NH(X 3Σ−) and ND(X 3Σ−) produced in the reactions of N(2 2D) with H2 and D2

Abstract

Two-photon dissociation of NO was employed to produce metastable atomic nitrogen N(2D) and to study its reactions. A mixture of NO and H2(D2) was irradiated with an intense laser pulse at 275.3 nm which dissociates NO to produce N(2D). Electronically ground state NH(ND) radicals could be detected as products of the N(2D)+H2(D2) reaction. The nascent rotational and vibrational state distributions of NH(ND) were determined by analyzing the laser–induced fluorescence spectra. The nascent vibrational population ratios, NH(v′′=1)/NH(v′′=0) and ND(v′′=1)/ND(v′′=0), were determined to be 0.8±0.1 and 1.0±0.1, respectively. These ratios are larger than the prior ones, but smaller than the recent results of quasiclassical trajectory calculations based on an ab initio potential energy surface. The rotational distributions of NH(ND) were very broad, both for the v′′=0 and v′′=1 levels. These results suggest that there are no specific attacking sites in these reactions.