Exploring the role of steric effect in the stability of clusters: Water hexamer as a test case

Steric effect is one of the most widely used concepts in chemistry and has long been known to play imperative roles in various phenomena. In this paper, on the basis of a quantitative description of steric effect, which is based on a new energy partition scheme where the total electronic energy is decomposed into contributions from three independent effects of steric, electrostatic, and the Fermionic quantum, the steric effects in different conformers of water hexamer have been investigated. It is shown that the steric repulsion has a strong effect on conformations stability. Reasonable correlations between relative electronic energies and steric energies are revealed. We find that more stable structures of water hexamer prefer to have smaller size and less steric repulsion. (C) 2014 Elsevier B. V. All rights reserved.