Modeling small hydronium-water clusters

We have developed new potentials to model the interactions between H₃ O + and H₂O and used them to investigate small H₃O + ⋯(H₂O) n clusters for n=1–7. The construction of the potentials uses monomer properties for the long-range interactions and perturbation theory for the short-range terms. We have extensively searched all the potential energy surfaces and discuss the low-energy minima that we have found. We extend the calculations for n=2, 4, and 5 by performing geometry optimizations using density functional theory, starting with minima found with the new model potential.