The exponential increase in the number of hydrogen bonded configurations with the number of waters in a cluster makes configurational sampling very critical. Exploring the massive potential energy surface is important not only to find the global minimum structure, but also to capture the ensemble of clusters that are thermally accessable at any finite temperature. For clusters containing up to seventeen waters, we have used reliable model potentials to sample a large number of clusters which were subsequently optimized using RI-MP2 and their energies extrapolated to the RI-MP2 complete basis set (CBS) limit. By combining the RI-MP2/CBS electronic energies with finite temperature thermodynamic corrections, the ensemble averaged Gibbs free energies are used to explain the thermodynamics of water cluster growth. Comparisons with structural information from rotational spectroscopy and thermodynamic information from homogeneous nucleation of water are also used to assess our theoretical predictions.

Approaches for getting benchmark structures and thermodynamics of large water clusters

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.