Dissociation scheme of highly charged triatomic molecules

Ionization of triatomic molecules in collision with 120 keV Ar(8+) and the subsequent molecular fragmentation has been studied by means of a position sensitive time-of-flight (TOF) technique. The triple coincidence signals for these molecules are identified for the dissociation channels of (CO(2))(n+) where n = 3 - 6. The dissociation of (NO(2))(n+) where n = 3 - 5 has also been studied. The velocity vector of each fragment ion is determined for individual collision events and the angle between the velocity vectors is calculated. For the highly ionized molecules (n = 6), the angle is consistent with the angle of the neutral molecule, both in the case of linear and bent molecules. For the lower charge states considerable deviation from the neutral molecule bond angle has been found. These results suggest that production of higher charge states is favorable for the fulfillment of a pure Coulombic dissociation scheme.