The novel technique of femtosecond time-resolved photoelectron-photoion coincidence imaging is applied to unravel dissociative ionization processes in a polyatomic molecule. Femtosecond coincidence imaging of ${\mathrm{CF}}_3\mathrm{I}$ photodynamics illustrates how competing multiphoton dissociation pathways can be distinguished, which would be impossible using photoelectron or ion imaging alone. Ion-electron energy correlations and photoelectron angular distributions reveal competing processes for the channel producing ($e^{-}+\mathrm{CF}_3{}^{+}+\mathrm{I}$). The molecular-frame photoelectron angular distributions of the two major pathways are strikingly different.

• Received 8 September 2003

DOI:https://doi.org/10.1103/PhysRevLett.92.123002