Collision Induced Dissociation for 1.5 keV/amu HeH$^{+}$ Impact on Argon*

Collision induced dissociation [CID, e.g. HeH$^{+}$ + Ar -$>$ H$^{+}$ + He] is measured for 1.5 keV/amu HeH$^{+}$ on argon using 3D momentum imaging techniques and compared to similar measurements with H$_{2}^{+}$. Unlike H$_{2}^{+}$, HeH$^{+}$ dissociation is dominated by vibrationally excited rather than electronically excited CID. This difference is explained in terms of the larger energy gap between the ground and excited states in HeH$^{+}$. An asymmetry in dissociation channels between H$^{+}$ and He$^{+}$ products is also observed and explained in terms of the potential energy curves.