A PULSED ION SOURCE FOR THE STUDY OF UNIMOLECULAR AND BIMOLECULAR REACTIONS OF GAS-PHASE IONS

Abstract

A pulsed ion source has been constructed for use with a magnetic-deflection mass spectrometer. With this source the time between ion formation and withdrawal for analysis can be controlled and varied in a known manner. The design and operating characteristics of the source are discussed and a technique is described for the measurement of ion withdrawal times using the pulsing technique. The rate constant for the ion molecule reaction[Formula: see text]has been determined for the reaction of thermal energy ions using reaction time as the experimental variable. The equivalent reactions in the deuteriomethanes have also been studied. Preliminary results obtained in the study of the unimolecular fragmentation of the cyclohexadiene, toluene, and spiroheptadiene parent ions are presented.