title: On the position of the highest occupied molecular orbital in aqueous solutions of simple ions.
abstract: The energies of the highest occupied molecular orbital (HOMO) of four simple microsolvated aqua ion clusters (Na+, Ag+, Cl-, CN-) are computed for varying numbers of water molecules. Extrapolating to infinite hydration numbers we find that these energies approach a value of -6 eV. This limiting one-electron energy is within a margin of +/-1 eV independent of the character of the ion and is 4 eV lower compared to the estimate obtained for the HOMO energy of the ions in aqueous solution under periodic boundary conditions. We argue that this discrepancy must the attributed to a shift in the reference of the one-electron potential of the periodic solvent model.
authors.affiliation: Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
authors.forename: Patricia
authors.initials: P
authors.lastname: Hunt
authors.forename: Michiel
authors.initials: M
authors.lastname: Sprik