Highly Accurate Coupled Cluster Potential Energy Curves for the Benzene Dimer:  Sandwich, T-Shaped, and Parallel-Displaced Configurations

State-of-the-art electronic structure theory has been applied to generate potential energy curves for the sandwich, T-shaped, and parallel-displaced configurations of the simplest prototype of aromatic π−π interactions, the benzene dimer. Results were obtained using second-order Møller−Plesset perturbation theory (MP2) and coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] with different augmented, correlation-consistent basis sets. At the MP2 level, the smallest basis set used (a modified aug-cc-pVDZ basis) underestimates the binding by ∼0.5 kcal mol-1 at equilibrium and by ∼1 kcal mol-1 at smaller intermonomer distances compared to results with a modified aug-cc-pVQZ basis (denoted…