Quantum mechanical probabilistic structure of the benzene-water complex

On the realistic energy hypersurface of the floppy benzene-water complex obtained with high-levels of ab initio theory, the experimental structure, rotational constants and binding energy cannot be described simply in terms of the equilibrium position, but need to be characterized in a quantum mechanical probabilistic way. In this way, the structure and rotational constants show excellent agreement with experiment, and the binding energy is in favor of the experimental upper bound. The most important component of the benzene-water binding energy is the electron correlation, followed by the interaction between the water dipole and benzene quadrupole.