ION-MOLECULE REACTIONS UPON STEPWISE PHOTOIONIZATION OF BENZENE AND TOLUENE

The mechanism of ion-molecule reactions involving benzene and toluene ions produced upon two-and three-photon ionization of the molecules wa s studied, and their reaction rate constants were determined. The vibr ational excitation energy of an ion decreases the rate constant of for mation of dimer cations via a trimolecular reaction mechanism. Electro nically excited benzene ions take part in two parallel processes: diss ociation of ions and collision deactivation of excited states. The kin etic energy of primary ions (up to 4 eV) does not affect the rate cons tant for both reactions.