Structural and dynamical studies of CH-π bonded CH4-C6H6 dimer by ultrafast intermolecular Coulombic decay

The inner-valence ionization and fragmentation dynamics of CH4-C6H6 dimer induced by 200 eV electron impact is studied utilizing a multi-particle coincidence momentum spectroscopy. The three-dimensional momentum vectors and kinetic energy release (KER) of the CH4 (+)+C6H6 (+) ion pairs are obtained by coincident momentum measurement. Our analysis on the absolute cross sections indicates that the intermediate dication CH4 (+)-C6H6 (+) is preferentially produced by the removal of an inner-valence electron from CH4 or C6H6 and subsequent relaxation of ultrafast intermolecular Coulombic decay followed by two-body Coulomb explosion. Combining with ab initio molecular dynamics (AIMD) simulations, the real-time fragmentation dynamics including translational, vibrational and rotational motions are presented as a function of propagation time. The revealed fragmentation dynamics are expected to have a potential implication for crystal structure imaging with various radiation sources.

Automated summary

The inner-valence ionization and fragmentation dynamics of CH4-C6H6 dimer induced by 200 eV electron impact are studied using multi-particle coincidence momentum spectroscopy. The three-dimensional momentum vectors and kinetic energy release (KER) of the CH4 (+)+C6H6 (+) ion pairs are measured through coincident momentum measurement. The analysis on the absolute cross sections reveals that the intermediate dication CH4 (+)-C6H6 (+) is preferentially formed by the removal of an inner-valence electron and subsequent relaxation, followed by two-body Coulomb explosion. Real-time fragmentation dynamics including translational, vibrational and rotational motions are presented based on ab initio molecular dynamics (AIMD) simulations. The revealed fragmentation dynamics have potential implications for crystal structure imaging with different radiation sources.