We have measured the rate constants for the reactions of Ar+ with CO2 and SO2 from 300 to 1500 K in a high temperature flowing afterglow. For the reaction with CO2, we have found that all modes of energy, i.e., translation, rotation, and vibration, affect the rate constant to the same degree up to a total energy of 0.4 eV. Above 0.4 eV total energy, internal energy decreases the rate constants more effectively than does translational energy. For the reaction of Ar+ with SO2, the rate constants go through a minimum at about 900 K. By comparing our results to drift tube data, we derive rate constants for reaction from the v = 0 and v > 0 vibrational levels. At low energy, the vibrationally excited SO2 molecules react with Ar+ approximately twice as fast as the ground state molecules. Both vibrational modes have similar temperature dependences.
|Number of pages||6|
|Journal||Journal of the American Society for Mass Spectrometry|
|State||Published - 1999|
Bibliographical noteFunding Information:
We dedicate this article to the memory of Bob Squires. His contributions to the field of ion chemistry are well known, insightful, and innovative, and therefore will long be remembered. More importantly, Bob was a good friend and interaction with Bob was not only stimulating but a lot of fun. He will be sorely missed. This research is supported by the Air Force Office of Scientific Research under task 2303EP4. We would like to thank Bob Morris and Skip Williams for helpful discussions.