Making Sense of Coulomb Explosion Imaging

A multifaceted
agreement between ab initio theoretical predictions
and experimental measurements, including branching ratios, channel-specific
kinetic energy release, and three-body momentum correlation spectra,
leads to the identification of new mechanisms in Coulomb-explosion
(CE) induced two- and three-body breakup processes in methanol. These
identified mechanisms include direct nonadiabatic Coulomb explosion
responsible for CO bond-breaking, a long-range “ inverse harpooning”
dominating the production of H2+ + HCOH+, a transient proton migration
leading to surprising energy partitioning in three-body fragmentation
and other complex dynamics forming products such as H2O+ and H3+. These mechanisms provide general concepts that should be
useful for analyzing future time-resolved Coulomb explosion imaging
of methanol as well as other molecular systems. These advances are
enabled by a combination of recently developed experimental and computational
techniques, using weak ultrafast EUV pulses to initiate the CE and
a high-level quantum chemistry approach to follow the resulting field-free
nonadiabatic molecular dynamics.