Effect of Translational Energy on Ion-Molecule Reaction Rates. I

Publisher Website
Google Scholar
Abstract
The specific reaction rates for reactions between ions and molecules when both the reacting partners have thermal energy only have been determined for several systems. These rates have been determined by using a combination of a pulsed ionizing beam followed by a variable time‐delay ion‐extraction pulse. The results are compared with the field strength dependent values obtained in the same source operated in the conventional manner. The apparent thermal rate constant for the reaction CH4++CH4→CH5++CH3 is 9.6×10−10 cm3 molecule−1 sec−1, but after correction is made for detector discrimination, the value becomes 17.0×10−10 cm3 molecule−1 sec−1. For the field strength dependent values the magnitude of the ionizing current has a strong effect upon the observed specific reaction rate. Operation under conditions where the ionizing current is 0.1 μA led to reproducible values for the specific reaction rates.