Velocity and charge state dependences of molecular dissociation induced by slow multicharged ions

Dissociation of CO molecules by collisions with He2+ and O7+ at keV energies has been investigated by measuring the charge states and kinetic energies of the ionized fragments in coincidence with each other. As opposed to earlier investigations with fast (MeV) projectiles we find that the kinetic energies of the fragment ions are strongly influenced by the projectiles' charge and velocity; e.g., O7+ impact results in 50% less kinetic energy release in the C+-O+ fragmentation than He2+ impact. For a qualitative understanding of these effects we invoke the classical overbarrier model

Irradiation of benzene molecules by ion-induced and light-induced intense fields

Benzene, with its sea of delocalized $\pi$-electrons in the valence orbitals, is identified as an example of a class of molecules that enable establishment of the correspondence between intense ion-induced and laser-light-induced fields in experiments that probe ionization dynamics in temporal regimes spanning the attosecond and picosecond ranges.Comment: 4 ps figure

Kinetic Energy Release of Dissociation CO^{3+} Ions Produced in Collisions of Multiply Charged Ions with CO

We investigate fragmentation of CO molecules by collisions of He2+ ions at energies between 2 and 11 keV/amu by means of a reflectron time-of-flight (TOF) spectrometer. The kinetic-energy-release (KER) in the center of mass system of the molecule can be determined from the flight times of these particles. Different dissociation processes leading to different amounts of released energy and different fragments can be identified. The KER differs from the one expected from the pure Coulomb repulsion of two point charges, starting at the CO equilibrium distance and depended strongly on the collision energy. This will be discussed in terms of the classical overbarrier model. Furthermore, there is a strong influence of the projectile type on the KER. A feature of the experiments, namely the strong dependence of the KER on the projectile kinetic energy, is not yet fully understood