Negative ion-molecule reactions at low collision energies

A pulsed mass spectrometer has been used to measure the rate constants of the following negative ion-molecule reactions {A figure is presented} as a function of temperature and ion kinetic energy from the thermal range to about 1 eV. Reactions (1), (2) and (5) were found to have rate constants which increase with increasing ion kinetic energy as well as with temperature. Reactions (3) and (4), on the other hand, have rate constants which decrease with energy and temperature.