Toward the Study of Astrochemical Reaction Dynamics With Ion Imaging Techniques

Abstract

We present new results for some astrochemically relevant reaction processes obtained using reflectron velocity map ion imaging and Megapixel ion imaging techniques developed in our laboratory recently. Using reflectron multimass velocity map ion imaging, we studied the vibrationally mediated photodissociation dynamics in the ethylene cation. We simultaneously record spatially resolved images of parent C2H4+ ions as well as photofragment C2H3+ and C2H2+ ions originating in dissociation from the vibronic excitations in two distinct bands, 7f 402 and 8f 000, at roughly the same total energy. The experimental results are discussed in terms of the possible influence of the torsional excitation on competition between direct dissociation, isomerization, and radiationless transitions through conical intersections among the numerous electronic states that participate in the dissociation. In conjunction with dc slice imaging, the Megapixel ion imaging technique can improve the resolution up to ten times higher than...