Unimolecular and bimolecular reactions of state selected HCl+ ions formed via the R(1) pump line of the f3Δ2←1Σ+ REMPI spectrum
The properties of HCl+ ions formed in the vibronic ground state 2Π3/2 (″ = 0) ia the R(1) pump line of the f3Δ2←1Σ+ REMPI spectrum have been investigated. In the first experiment the rotational state distribution of these ions has been determined by photoexcitation into the A2Σ+(′ = 7) state, which can predissociate. 73% of the HCl+ ions are found in the N″ = 0 state, 23% in the N″ = 1 and 4% in the N″ = 2 state. This experiment also yields the spectroscopic parameters of the A2Σ+(′ = 7) state and information on the rotational dependence of the predissociation lifetimes of this state. The threshold for predissociation occurs between the N′ = 0, J′ = 1/2 and the N′ = 1, J′ = 1/2 state, leading to a new dissociation energy of the HCl+ ion of D0 = 37536.5 cm−1±5 cm−1. In the second experiment these state-selected HCl+ ions are investigated in an ion–molecule reaction with carbon monoxide. In this reaction very efficient proton transfer leads to the formation of HCO+ with a rate constant close to the Langevin limit.