Extra electron in (H2O)24- cluster isomers: a theoretical study

The isomers of (H(2)O)(24) (-) tetrakaidecahedral cluster are studied by applying the Becke-3-parameter density functional theory and Lee-Yang-Parr correlation functional (B3LYP) and 6-311++G** basis set. Three isomers are selected on the basis of stabilization energy values. The vertical electron dissociation energies (VDE) of these isomers are 1.353, 0.404, and 0.258 eV, respectively. The experimental VDE value of 1.31 eV J. Chem. Phys. 92, 3980 (1990)] for this cluster size is in excellent agreement with that calculated for isomer 1, suggesting the dominance of this isomer in the experiment. Four water molecules in this isomer share most of the -1 charge. These four water molecules have non-H-bonding H (NHB H) atoms turned toward the cavity, and the inward turned H atoms exhibit a significant lowering of O-H stretch frequency compared to that of a monomer. Isomers 2 and 3 have all 12 NHB H atoms projected outward and have the -1 charge distributed among 7-8 water molecules on the cluster surface.