Photodissociation dynamics of ClN3 at 203 nm: the NCl (a1Δ/X3Σ−) product branching ratio

Velocity map imaging was applied to study the photodissociation dynamics of ClN3 near 203 nm under collision free conditions. Images of state-selected N2(X1Σg+, ν=0, J=68) characterize the internal energy of the photofragments and reveal the energetics of reactions (*) and (**): (*)ClN3→N2(X1Σg+)+NCl(a1Δ) ΔE=+0.21±0.07 eV(**)ClN3→N2(X1Σg+)+NCl(X3Σ−) ΔE=−0.93±0.08 eVThese 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 B̃1A′←X̃1A′ excitation is the most important pathway to photoproducts. Branching measurements between the dominant spin-allowed channel (1) and the spin-forbidden channel (2) showed a1Δ/X3Σ−=0.78/0.22.