Fragmentation of highly charged molecular ions or clusters consisting of more than two atoms can proceed in a one step synchronous manner where all bonds break simultaneously or sequentially by emitting one ion after the other. We separated these decay channels for the fragmentation of ${\mathrm{CO}}_2^{3+}$ ions by measuring the momenta of the ionic fragments. We show that the total energy deposited in the molecular ion is a control parameter which switches between three distinct fragmentation pathways: the sequential fragmentation in which the emission of an ${\mathrm{O}}^{+}$ ion leaves a rotating ${\mathrm{CO}}^{2+}$ ion behind that fragments after a time delay, the Coulomb explosion and an in-between fragmentation—the asynchronous dissociation. These mechanisms are directly distinguishable in Dalitz plots and Newton diagrams of the fragment momenta. The ${\mathrm{CO}}_2^{3+}$ ions are produced by multiple electron capture in collisions with $3.2\mathrm{keV}/\mathrm{u}$ ${\mathrm{Ar}}^{8+}$ ions.

• Received 14 August 2009

DOI:https://doi.org/10.1103/PhysRevLett.104.103201