HCl-induced molecule fragmentation: non-Coulombic explosion and three-bodyeffects

The study of Highly Charged Ion-induced diatomic (CO) and triatomic (CO2) m olecules fragmentation by the coincident measurement of the fragment moment a is presented. It is shown that the experimental results together with ab initio calculations including a large number of potential energy curves evi dence the limitation of the Coulomb Explosion model to reproduce the dynami cs of the fragmentation. The geometry modification of the CO2 molecule duri ng the breakup is explored and the concerted or sequential nature of the di ssociation is discussed for two fragmentation channels. Finally, the fragme ntation of the H-2 molecules following collisions with slow multicharged io ns is analysed for various projectiles and energies. From the energy spectr a, the effect of the projectile on the H+ fragments is evidenced. This thre e-body effect is discussed in connection with the results of two model calc ulations including or not the role of the projectile.