Assessment of Some Density Functional Theory Methods and Force Field Models in Describing Various Interaction Modes of Benzene Dimer

Benzene dimer (bz2) is the simplest prototype of the π-π interactions. Such interactions are ubiquitous in diverse areas of science and molecular engineering. In the present work, we have made assessment on some modern density functional methods including B97-D, BLYP-D3, M06-2X, XYG3, and force field models including CHARMM, AMBER, MM3, AMOEBA on six important interaction modes of bz2. Our results not only highlight the usefulness of these cost-effective methods, which can be used as economic substitutes of the expensive CCSD(T) for complex real-world systems, but also indicate their weakness in the description of the π-π interactions, which points to the future direction for further improvements.