Proton transfer reactions of H+(H2O)n=2ndash;11with methanol, ammonia, pyridine, acetonitrile, and acetone

摘要

We report here the first measurements of rate constants involving cluster ions with more than five ligands. We have measured rate constants, or lower limits to rate constants, for the reactions of H+(H2O)n=2ndash;11with NH3, CH3CN, CH3OH, CH3COCH3, and C5H5N (pyridine). The experimental techniques needed to study these ions and neutrals at low temperatures are described. The reactions all proceed rapidly by proton transfer with varying degrees of ligand transfer. At low temperatures the rate constants are larger than the collision rate constant based on an ionndash;dipole potential. Reasons for this are examined. Thermal dissociation appears to control the size distribution of the primary ion clusters and to affect the observed product distribution.