Comparative study of the ground-state dissociation of H-2(+) and D-2(+) induced by ionizing and electron-capture collisions with He+ at velocities of 0.25 and 0.5 a.u. - art. no. 042710

摘要

The ground-state dissociation (GSD) of H-2(+) and D-2(+) molecular ions induced by ionizing and electron-capture collisions of He+ projectiles with hydrogen and deuterium molecules was investigated at impact velocities of 0.25 and 0.5 a.u. Momentum distributions of slow H+ and D+ fragments were measured and compared with calculations based on GSD theory. At the higher velocity, and for both capture and ionization, these distributions are well accounted for by a model that attributes the momenta to the vibrational wave function of the parent H-2 or D-2 molecule. For the lower velocity, this model remains successful for capture but not for ionization. For the latter case we observe a large transverse-momentum component imparted to the vibrationally excited H-2(+) or D-2(+) system beyond that predicted by the model. This feature is interpreted as being caused by momentum transferred to the motion of the nuclei within the molecule's center-of-mass frame by way of a direct interaction between the projectile and one of the molecule's nuclei. [References: 17]