Low-lying isomers and finite temperature behavior of (H2O)(6)(-)

摘要

(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 , 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. (c) 2006 American Institute of Physics.