Structures, energies, and spectra of aqua-silver (I) complexes

Abstract

Owing to the utility of redox phenomena of silver in many chemical systems, it is important to understand the coordination chemistry of Ag+ ion and hence the hydration structure. The lowest-energy conformations of Ag+(H2O)(1-6) are sensitive to the calculation method employed. The coordination number (N-c) of Ag+(H2O)(n) is predicted to be 2 for n=2-6 at the density functional theory level, while the N-c for n=3-5 is 3, and that for n=6 is 4 at the second-order Moller-Plesset perturbation level. Further accurate analysis based on coupled-cluster singles and doubles theory with perturbative corrections for triple excitations agrees with the MP2 results except that N-c of 4 is also as competitive as N-c of 3 for n=5. To identify the correct N-c, it would be useful to facilitate the IR experimental characterization. We thus provide the OH spectra for various possible structures. It is interesting to note that the hydration chemistry of Ag+ ion is somewhat different from that of alkali metal ions. (C) 2003 American Institute of Physics.