Ion-induced molecular fragmentation: beyond the Coulomb explosion picture

Abstract

The fragmentation of the CO molecule by O 7+ ion impact is investigated in two different energy regimes by fragment ion momentum spectroscopy. The improved resolution of the present kinetic energy release measurement together with application of a time-dependent wavepacket dynamics method used in conjunction with new high-level computations of a large number of dication potential energy curves enables one to unambiguously assign each line to an excited state of the transient molecular dication produced during the collision. This is the first direct experimental evidence of the limitations of the Coulomb explosion model to reproduce the molecular fragmentation dynamics induced by ion impact. Electron removal due to a capture process is shown to transfer less excitation to the target than direct ionization. At low collision velocity, the three-body interaction between the projectile and the two fragments is also clearly highlighted.

Formation ofH3+due to Intramolecular Bond Rearrangement in Doubly Charged Methanol

“…This kinetic energy primarily arises from the Coulomb repulsion between H 3 and the rest of the charged molecular fragments. Such values are lower than those typically expected upon pure Coulomb explosion of multiply charged molecules [8]. This clearly implies that the molecular rearrangement occurs well before the Coulomb explosion happens.…”

Setup for measuring angular anisotropies in slow ion-molecule collisions

“…Several aspects of ion-impact molecular dissociation have been addressed using these powerful instruments, such as limitations of the Coulomb explosion model to reproduce molecular fragmentation dynamics [4], orientation effects in multiple ionization of molecules by fast ions [5] and studies on intra-molecular bond rearrangements in ion-molecule collisions [6].…”

Electron Capture in Collisions of Slow Highly Charged Ions with an Atom and a Molecule: Processes and Fragmentation Dynamics

“…In particular, much work has been devoted to simple molecular targets such as D 2 and H 2 [27,31,44] or CO [28,[45][46][47],. However, the fragmentation depends strongly onto the primary process, i.e.…”