Consecutive ion—molecule reactions in acetylene investigated by charge exchange mass spectrometry

Abstract

The consecutive ion—molecule reactions in acetylene within the pressure limits of 10 −5 and ▪ torr have been investigated as a function of the energy transferred to the acetylene molecule during the initial ionization by charge exchange with incident positive ions of low kinetic energy. The reactions of the molecular ion in the ground electronic state (π u −1) are distinguished from those of the molecular ion in an excited electronic state (σ g −1). The various chain sequences of reaction, including those involving ions with uneven numbers of carbon atoms, are elucidated, and numerous reactions proposed by earlier workers are shown to unimportant in the pressure range investigated. Rate constants are calculated for the various ion—molecule reactions.