Systematic Analysis of Four-Particle Dalitz Plots for Double Ionization

Using a split-mirror setup attached to a Reaction Microscope at the Free electron LASer in Hamburg (FLASH) we traced as function of time the migration of a hydrogen atom in C2H4+ from one end of the molecule to the other by coincident CH+ + CH3+ fragment detection. In addition, the observed H3++C2H+ channel provides for the first time evidence for an isomerization-induced formation mechanism of H3+ molecules.