Photodissociation dynamics of C1N3 at 203 nm:: the NCl (a1Δ/X3Σ-) product branching ratio

Velocity map imaging was applied to study the photodissociation dynamics of CIN3 near 203 nm under collision free conditions. Images of state-selected N-2(X(1)Sigma(g)(+), v = 0, J = 68) characterize the internal energy of the photofragments and reveal the energetics of reactions (*) and (**): ClN3 --> N-2(X(1)Sigma(g)(+)) + NCl(a(1)Delta) DeltaE = +0.21 +/- 0.07eV (*) ClN3 --> N-2(X(1)Sigma(g)(+)) + NCl(X(3)Sigma(-)) DeltaE = -0.93 +/- 0.08eV (**) These experiments provide the most accurate thermodynamics for these reactions presently available and are in good agreement with other recent experimental results. Photofragment angular distributions indicate that (B) over tilde (1) A' <-- (X) over tilde (1) A' excitation is the most important pathway to photoproducts. Branching measurements between the dominant spin-allowed channel (1) and the spin-forbidden channel (2) showed a(1)Delta/X(3)Sigma(-) = 0.78/0.22. (C) 2002 Elsevier Science B.V. All rights reserved.