title: Low-lying isomers and finite temperature behavior of (H2O)6 -.
abstract: (H2O)(6) (-) appears as a "magic" number water cluster in (H2O)(n) (-) mass spectra. The structure of the (H2O)(6) (-) isomer dominating the experimental population has been established only recently [N. I. Hammer et al., J. Phys. Chem. A 109, 7896 (2005)], and the most noteworthy characteristic of this isomer is the localization of the excess electron in the vicinity of a double-acceptor monomer. In the present work, we use a quantum Drude model to characterize the low-energy isomers and the finite temperature properties of (H2O)(6) (-). Comparison with ab initio calculations shows that the use of a water model employing distributed polarizabilities and distributed repulsive sites is necessary to correctly reproduce the energy ordering of the low-lying isomers. Both the simulations and the ab initio calculations predict that there are several isomers of (H2O)(6) (-) significantly lower in energy than the experimentally observed species, suggesting that the experimental distribution is far from equilibrium.
authors.affiliation: Department of Chemistry and Center for Molecular and Materials Simulation, University of Pittsburgh, Chevron Science Center, Pittsburgh, PA 15260, USA. tsom@pitt.edu
authors.forename: Thomas
authors.initials: T
authors.lastname: Sommerfeld
authors.forename: Suzanne D
authors.initials: SD
authors.lastname: Gardner
authors.forename: Albert
authors.initials: A
authors.lastname: DeFusco
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Jordan