Global Potential Energy Minima of $(H_2O)_n$ Clusters on Graphite: A Comparative Study of the TIP$N$P ($N=3,4,5$) Family

TL;DR

This study compares the global energy minima of water clusters on graphite using three TIP$N$P models, revealing differences in favored structures and the influence of water-water interaction models on cluster conformations.

Contribution

It provides a comparative analysis of water cluster conformations on graphite using basin-hopping optimization and three TIP$N$P models, highlighting model-dependent structural preferences.

Findings

TIP3P favors monolayer structures for small clusters.

TIP4P and TIP5P favor bilayer or volume structures for larger clusters.

Water-water interaction models influence the hydrophobic behavior threshold.

Abstract

The water-graphite interaction potential proposed recently (Gonz\'alez et al.\emph{J. Phys. Chem. C} \textbf{2007}, \emph{111}, 14862), the three TIP$N$P ($N=3,\:4,\:5$) water-water interaction models, and basin-hopping global optimization are used to find the likely candidates for the global potential energy minima of (H$_{2}$O)$_{n}$ clusters with $n\leq21$ on the (0001)-surface of graphite and to perform a comparative study of these minima. We show that, except for the smaller clusters ($n<6$), for which ab-initio results are available, the three water-water potential models provide mostly inequivalent conformations. While TIP3P seems to favor monolayer water structures for $n<18$, TIP4P and TIP5P favor bilayer or volume structures for $n>6$. These $n$ values determine the threshold of dominance of the hydrophobic nature of the water-graphite interaction at the nanoscopic scale for these potential models.