Kinetic energy release in electron-induced decay reactions of molecular ions: C[sub 3]H[sub 8][sup +] and C[sub 3]H[sub 7][sup +].

We have measured the kinetic energy release (KER) distributions for electron-induced dissociation of mass-selected molecular parent and fragment ions of propane. They are compared with distributions determined for spontaneous (metastable) dissociation. The average KER for induced dissociation of C[sub 3]H[sub 8][sup +] into C[sub 3]H[sub 7][sup +] is 13.2±1.2 meV, about 42% larger than for the spontaneous reaction. This large difference is attributed to the dramatically reduced time at which the induced reaction can be sampled. In contrast, the KER for dissociation of C[sub 3]H[sub 7][sup +] into C[sub 3]H[sub 5][sup +], which is characterized by a large reverse activation energy, is hardly affected by the experimental time scale. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]