Comparison of the nuclear motion in the ultrafast fragmentation of SF₆, CF₄ and CH₃F

Resonant F 1 s excitation of SF₅, CF₄ and CH₃F molecules has been used to initiate ultrafast fragmentation. In all these reactions the fragmentation is fast enough so that atomic-like Auger decay can happen at large internuclear distances. The detection of an atomic-like F 1 s Auger electron allows to focus on the study of this reaction channel. We analyzed the kinetic energy of the F⁺ fragment that is detected after an atomic-like Auger electron has been emitted using high-resolution electron-ion momentum coincidence spectroscopy. In this way we could study the kinetic energy release of the fragmentation as a function of the excitation energy. The results indicate that the nuclear motion within the radical remainder SF₅, CF₃ and CH₃ must be considered to understand the fragmentation dynamics.