Production of Hydrated Metal Ions by Fast Ion or Atom Beam Sputtering. Collision-Induced Dissociation and Successive Hydration Energies of Gaseous Cu+ with 1-4 Water Molecules

Low-temperature sputtering of frozen aqueous solutions of metal salts, of hydrated crystalline transition-metal salts, of frosted metal surfaces, and of frosted metal salts with kiloelectronvolt energy rare gas atoms or ions produces copious amounts of cluster ions, among which M+(H2O)n and/or M+OH(H2O)n frequently dominate. Variable-energy collision-induced dissociation of these ions in a triple quadrupole mass spectrometer yields the successive gas-phase solvation energies. Several known hydration and bond energies have been reproduced, and the first and second hydration energies of the Cu+ ion have been determined as 35 ± 3 and 39 ± 3 kcal/mol, respectively. It is concluded that gaseous Cu+ prefers dicoordination.