Theoretical Study of Microscopic Solvation of Lithium in Water Clusters: Neutral and Cationic Li(H2O)n (n = 1−6 and 8)
journal contributionposted on 01.04.1998, 00:00 by Kenro Hashimoto, Tetsuya Kamimoto
The structure, stability, and electronic state of Li(H2O)n (n = 1−6 and 8) clusters have been investigated by an ab initio molecular orbital method, including electron correlation, and compared with those of their cations. The interior structure where the Li atom is surrounded by four H2O molecules in the first shell and more in the second shell is found to be the most stable for both neutral and cationic n ≥ 4 clusters. The size dependence of the vertical ionization potentials of Li(H2O)n is in good agreement with the recent experiment. It decreases successively until n = 4 and becomes nearly constant for n ≥ 4 being close to the bulk limit of vertical detachment energies of (H2O)n-. The excess electron is separated from Li and distributed outside the first-shell cavity in n ≥ 4 clusters. The electronic state of the clusters changes from a one-center atomic state for n ≤ 3 to a two-center ionic state for n ≥ 4 with a gradual localization of the excess electron. Dangling hydrogens interacting with the excess electron play a role as actuators of the surface state.