Crossed beam studies of low energy proton transfer reactions: H2+(Ar,H) HAr+ from 0.4 to 7.8 eV (c.m.)

We present a crossed beam study of the proton transfer reaction H2+ (Ar,H) HAr+ over an extended energy range. At the lowest collision energies (∼0.4 eV), the reaction appears to proceed with substantial interaction among all three atoms, while the dynamics become ’’direct’’ in the higher energy regime. Collision induced dissociation of the HAr+ product is observed for collision energies above ∼2 eV, but products with internal energy in excess of the HAr+ dissociation limit are observed in all cases. These observations are rationalized in terms of the metastability of HAr+ products with rotational energy in excess of the dissociation limit. A surprisal analysis on the product translational energy distributions is also presented.