Unimolecular reaction dynamics from kinetic energy release distributions. IV. Dissociation of the pyridine ion

The kinetic energy release distribution (KERD) for the dissociation of the pyridine ion into C4H4.+ + HCN in the microsecond time window has been expe rimentally determined and theoretically analyzed by the maximum entropy met hod. Less energy is channeled into the reaction coordinate than the statist ical estimate because of the action of the "momentum gap law." The larger t he value of the relative translational momentum of the fragments, the less efficient the exploration of phase space. The fraction of phase space effec tively sampled is estimated to be of the order of 75%. (Int J Mass Spectrom 185/186/187 (1999) 155-163) (C) 1999 Elsevier Science B.V.