Vibrational energy disposal in polyatomic ion–molecule reactions: SF⁻₆+H, D→SF⁻₅+HF(v), DF(v)

Vibrational state distributions of the SF⁻₆+H, D→SF⁻₅ +HF(v=0–12), DF(v=0–17) ion–molecule reactions are investigated with the flowing afterglow‐infrared chemiluminescence technique. The nascent distribution for the hydrogen reaction is (0.00)_v=1 : (0.17)_v=2 : (0.30)_v=3 : (0.24)_v=4 : (0.13)_v=5 : (0.11)_v=6 : (0.05)_v=7 and for the deuterium reaction is (0.00)_v=1 : (0.06)_v=2 : (0.11)_v=3 : (0.14)_v=4 : (0.14)_v=5 : (0.23)_v=6 : (0.15)_v=7 : (0.08)_v=8 : (0.09)_v=9. The fractions of the available energy deposited into the HF and DF vibrations are 0.37 and 0.38, respectively. The distributions do not show the characteristics of a statistical distribution that might be expected if a long‐lived complex occurs in the reaction. Instead, the distributions show a moderate amount of vibrational excitation due to an initial attractive energy release. Since the fraction of the available energy deposited into the diatomic vibration correlates well with the attractive energy release in L+HH′ systems, a larger fraction of the energy is released as repulsion during S–F bond scission, favoring product translation and SF⁻₅ vibration. The collisions are most likely direct with negligible effects due to secondary encounters.