Deuterium isotope effects in collision-induced dissociation and photodissociation of the (N2O,H2O)+ cluster ion

Abstract

We present low energy collision-induced dissociation (CID) and visible photodissociation (PD) data of jet-cooled (N2O,H2O/D2O)+ cluster ions. The same three fragment ions are observed in both CID and PD, namely, H2O+/D2O+, N2O+, and N2OH+/N2OD+. The H2O+ and N2O+ product channels exhibit a small deuterium isotope effect in both CID (10%) and PD (15%). The N2OH+ product channel, on the other hand, exhibits a much larger deuterium isotope effect for CID (30%) and PD (230%). The large difference in deuterium isotope effects observed in the N2OH+ product channel for CID and PD suggests that this product is formed via collision-induced and photoinduced proton-transfer reactions. These results are consistent with the interpretation that a single isomeric form, namely a (N2O⋅H2O)+ association complex, predominates. No evidence is found supporting the existence of a proton-transfer complex, i.e., N2OH+⋅OH. Evidence for the formation of minor amounts of a weakly bound isomeric form with the charge localized on the H2O moiety, i.e., N2O⋅H2O+, is found.