Flowing Afterglow Infrared Chemiluminescence Studies of Vibrational Energy Disposal in the Ion-Molecule Reactions F- + HBr,DBr Yields HF,DF + Br-

摘要

Product vibrational state distributions for the ion-molecule reactions F(-) + HBr,DBr yields HF(v< or = 4), DF(V < or = 6) + Br(-) are determined using the flowing afterglow infrared chemiluminescence technique. The nascent distributions are (0.09 + or - 0.04)v=1:(0.29 + or - 0.04)v=2:(0.34 + or - 0.04)v=3:(0.28 + or - 0.04)v=4 for the HF product, and (0.05 + or - 0.04)v=1:(0.12 + or -0.04)v=2:(0.16 + or - 0.04)v=3:(0.25 + or - 0.04)v=4:(0.22 + or - 0.04)v=5:(0.20 + or - 0.04)v=6 for the DF product. The fractions of the available energy deposited in product vibration are 0.60 + or -0.04 and 0.63 + or - 0.05 for the proton transfer and deuteron transfer reactions, respectively. A surprisal analysis suggests that less than 5% of the product molecules are formed in v = 0. The HF distribution is somewhat hotter than that reported previously, while the DF distribution is measured for the first time. Both distributions are remarkably similar to those reported for the analogous neutral processes, which suggests that direct collisions dominate the reactive encounters despite the presence of a deep attractive well in the potential surface for the ion-molecule reactions. (Author)