Development of an Efficient Geometry Optimization Method for Water Clusters

A geometry optimization method for water clusters (H2O)(n) was developed in the present study. The method was applied to the TIP3P and TIP4P water clusters in the range of n <= 30, and the resulting structures were compared with the global-minimum structures in the literature (n <= 25 for the TIP3P potential and n <= 30 for the TIP4P potential). The method failed to reproduce the previously reported global minimum of the n = 24 TIP4P cluster. However, it was possible to find new global minima for the n = 24, 26-30 TIP3P cluster and the TIP4P clusters of 25, 28, 29, and 30 molecules.