Reactions of Protonated Water Clusters H+(H2O)n (n=2 and 4) with D20, Acetonitrile, Acetone, DMS, DMSO, and Pyridine

Abstract

Reaction cross sections, σr, for reactions of protonated water clusters, H+(H2O)n (n = 2 and 4), with various compounds (i.e., X = D2O, acetonitrile, acetone, dimethyl sulfide (DMS), dimethylsulfoxide (DMSO), and pyridine) were measured at the collision energies of 0.05−2.0 eV by using a guided ion beam apparatus. It was found that the σrs of H+(H2O)2 were larger than those of H+ (H2O)4 when the proton affinity of X was almost equal to or greater than that of (H2O)2. In such cases, the dominant reaction products were in the form of H+X. These findings suggest that the enhancement of σr at n = 2 was due to a reaction pathway in which a proton is transferred directly from H+(H2O)2 to X without forming an intermediate complex.