Collision-Induced Intersystem Crossing of NH(a1Δ, v''= 0.1) by N2 and Xe: Temperature Dependence (N2) and Product States (N2, Xe)

Article abstract of DOI:10.1021/j100180a013

The elementary reactions of NM(a¹Δ,v''=0) with N2 and Xe have been studied in the gas phase.NH(a,v'') was produced by laser photolysis of HN3 at λ_l = 248 nm and λ_L = 308 nm and detected directly by laser-induced fluorescence (LIF) via the c¹Π-a¹Δ) transition.Time resolution is based on the delay between the photolysis and the probe laser.The reaction rates were determined under pseudo-first-order conditions ( >>a,v'')>₀), at different temperatures in the range 290 a,v''=0) + N2 -> products (1), k₁ = (3.9 +/- 1.2) * 10¹¹ exp(-(5.4 +/- 1.2) kJ mol^-1/RT)cm³/(mol s); NH(a,v''=1) + N2 -> products (2), k₂ = (8.6 +/- 2.7) * 10¹¹ exp(-(4.4+/- 2.3) kJ mol^-1/RT) cm³/(mol s); ND(a,v''=0) + N2 -> products (3), k₃ = (4.7 +/- 1.7) * 10¹¹ exp(-(5.2 +/- 1.1) kJ mol^-1/RT) cm³/(mol s).The NH(X,v), which appeared as the product of physical quenching, was detected by LIF with the transition (A³Π-X³Σ^-).In the reaction 1, 2, and 3 NH(X) and ND(X), respectively, were formed only in the vibrational ground state.The rate constant for the process NH(a,v''=1) + Xe -> products (5) was determined to be k₅ = (7.7 +/- 0.9) * 10¹² cm³/(mol s).In the physical quenching of NH(a,v'') (produced at λ_L = 248 nm) by Xe vibrationally vibrationally excited NH in the electronic ground sate NH(X,v=0,1,2) was detected NH(a,v''=0) (produced at λ_L = 308 nm) was quenched to NH(X,v=0).The different quenching dynamics of NH(a,v'') by N2 and Xe are discussed.