Electronic excitation of NO by the ion/ion neutralization reaction between NO + and C 6F 5CF 3− at thermal energy

Abstract

The ion/ion neutralization reaction between NO +(X 1 Σ +: v″ = 0) and C 6F 5CF 3 − has been spectroscopically studied in the flowing helium afterglow. The NO(A 2 Σ +-X 2II r, C 2II r-X 2II r, D 2Σ +-X 2II r) emission systems are observed in the NO +/C 6F 5CF 3 − reaction, as in the NO +/C 6F 6 − reaction reported previously. The same electronic state selectivity between the NO +/C 6F 5CF 3 − and NO +/C 6F 6 − reactions suggests that the molecular symmetry of the negative ion is insignificant for the electronic state selectivity in the ion/ion neutralization reaction. The relative formation rates of NO(A), NO(C), and NO(D) in the NO +/C 6F 5CF 3 − reaction are evaluated to be 1.0, 0.41 ± 0.003, 0.060 ± 0.010, respectively. Only the v′ = 0 levels of NO(A,C,D) are formed, indicating that no energy is deposited into the vibration of NO(A,C,D). The rotational distributions of NO(A: v′ = 0), NO(C: v′ = 0), and NO(D: v′ = 0) are expressed by single Boltzmann rotational temperatures of 500 ± 50 K, 300 ± 50 K and 400 ± 50 K, respectively. The average fractions of the total available energy deposited into rotation of NO(A), NO(C), and NO(D) are evaluated to be only 1.8 ± 0.2%, 1.4 ± 0.2%, and 2.5 ± 0.3%, respectively. The observed vibrational and rotational distributions are compared with statistical prior ones in order to obtain information on the dynamical feature of the reaction.