On the asymmetry in the angular distribution of the fragments produced from the collision induced dissociation of HD+ion

Abstract

The recently observed asymmetry in the forward and backward scattering of the fragments produced from the collision induced dissociation of heteronuclear molecular ions has been explained by considering their dipole moments. For simplicity, the electron impact dissociation of the HD+ ion for the 1s sigma 2 Sigma g+ to 2p sigma 2 Sigma u+ transition has been considered by applying the Born-Oppenheimer approximation. To include the effect of the dipole moment of the molecular ion, exchange scattering has also been considered. The results show that the inclusion of the electron-dipole interaction term in the Hamiltonian cannot explain the observed asymmetries. It is suggested that the asymmetry is due to the preferential orientation of the molecular ions due to the effect of the accelerating field on the dipole moment of the ions in the ion source chamber.