Ultrafast fragmentation dynamics of triply charged carbon dioxide: Vibrational-mode-dependent molecular bond breakage

Abstract

The $ab\phantom{\rule{0.16em}{0ex}}initio$ molecular dynamics (MD) simulations using an atom-centered density matrix propagation method have been carried out to investigate the fragmentation of the ground-state triply charged carbon dioxide, ${\mathrm{CO}}_{2}{}^{3+}\phantom{\rule{4pt}{0ex}}\ensuremath{\rightarrow}\phantom{\rule{4pt}{0ex}}{\mathrm{C}}^{+}$ + ${\mathrm{O}}_{\text{a}}{}^{+}$ + ${\mathrm{O}}_{\text{b}}{}^{+}$. Ten thousands of trajectories have been simulated. By analyzing the momentum correlation of the final fragments, it is demonstrated that the sequential fragmentation dominates in the three-body dissociation, consistent with our experimental observations which were performed by electron collision at impact energy of 1500 eV. Furthermore, the MD simulations allow us to have detailed insight into the ultrafast evolution of the molecular bond breakage at a very early stage, within several tens of femtoseconds, and the result shows that the initial nuclear vibrational mode plays a decisive role in switching the dissociation pathways.