Investigation of the carbon monoxide dication lifetime using (CO)2 dimer fragmentation

The fragmentation of carbon monoxide dimers induced by collisions with low-energy Ar9+ ions is investigated using the cold target recoil ion momentum spectroscopy technique. The presence of a neighbor molecule in the dimer serves here as a diagnostic tool to probe the lifetimes of the CO2+ molecular dications resulting from the collision. The existence of metastable states with lifetimes ranging from 2 ps to 200 ns is clearly evidenced experimentally through a sequential three-body fragmentation of the dimer, whereas fast dissociation channels are observed in a so-called concerted three-body fragmentation process. The fast fragmentation process leads to a kinetic energy release distribution also observed in collisions with monomer CO targets. This is found in contradiction with the conclusions of a previous study attributing this fast process to the perturbation induced by the neighbor molecular ion.

Automated summary

The study investigates the fragmentation of carbon monoxide dimers induced by collisions with low-energy Ar9+ ions, revealing the presence of metastable states with different lifetimes for CO2+ molecular dications. Different fragmentation channels are observed, with the fast dissociation process contradicting previous conclusions attributing it to perturbations induced by neighbor molecular ions.