BONDING OF A WATER MOLECULE TO A COPPER ATOM

Ab initio molecular orbital calculations, including correlation effects and large basis sets, have been carried out on the interaction of a single Cu atom with a water molecule, Cu...OH2. The H2O molecule is found to be bound to Cu by 0.20 eV with nearly all of the binding coming at the correlation level. This is reduced to about 0.15 eV if correction for basis set superposition error is included. The shift in the bending frequency of water in the complex has been calculated and is in good agreement with the observed shift of this complex trapped in a low-temperature matrix. Results are also presented for the interaction of a Cu atom with two water molecules to assess the nonadditivity of the interaction.