Benzene water interaction: From gaseous dimers to solvated aggregates

A recent formulation of intermolecular interactions has been adopted to describe the C 6H 6-H 2O system by combining a few interaction components. The pure electrostatic contribution accounts for the quadrupole-dipole interaction and the remaining ones are represented as a combination of effective potential terms, containing one non directly transferable and two transferable parameters. The first one introduces a high flexibility to the potential function and the last ones, well depth and distance at the minimum associated to the different interaction pairs, have a defined physical meaning and are derived by exploiting the decomposability of molecular polarizabilities (without performing any fit). For a given decomposition, the transferable parameters are assumed to have an universal character and, thanks to the flexibility of the function, they may be used to describe the same system in different environments, even when the charge distribution varies. Predicted results for the C 6H 6-H 2O dimer are compared with ab initio calculations. The behavior of benzene solvated by several water molecules is investigated by performing molecular dynamics simulations and the results are relevant to define some basic features of the main solvation shells.