Photofragment translation spectroscopy of ClN3 at 248 nm:: Determination of the primary and secondary dissociation pathways -: art. no. 104305

Photofragmentation translational spectroscopy was used to identify the primary and secondary reaction pathways in the KrF laser (248 nm) photodissociation of chlorine azide (ClN3) under collision-free conditions. Both the molecular channel producing NCl (X (3)Sigma,a (1)Delta)+N-2 and the radical channel producing Cl (P-2(J))+N-3 were analyzed in detail. Consistent with previously reported velocity map ion imaging experiments [N. Hansen and A. M. Wodtke, J. Phys. Chem. A 107, 10608 (2003)] a bimodal translational energy distribution is seen when Cl atoms are monitored at m/z=35(Cl+). Momentum-matched N-3 counterfragments can be seen at m/z=42(N-3(+)). The characteristics of the observed radical-channel data reflect the formation of linear azide radical and another high-energy form of N-3 (HEF-N-3) that exhibits many of the characteristics one would expect from cyclic N-3. HEF-N-3 can be directly detected by electron-impact ionization more than 100 mu s after its formation. Products of the unimolecular dissociation of HEF-N-3 are observed in the m/z=14(N+) and m/z=28(N-2(+)) data. Anisotropy parameters were determined for the primary channels to be beta=-0.3 for the NCl forming channel and beta=1.7 and beta=0.4 for the linear N-3 and HEF-N-3 forming channels, respectively. There is additional evidence for secondary photodissociation of N-3 and of NCl. (c) 2005 American Institute of Physics.