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

Abstract

Abstract 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.