# Communication: Accurate description of interaction energies and three-body effects in weakly bound m

The Journal of Chemical Physics **2018**

**DOI: **10.1063/1.5042153

We apply a recently developed parameter-free double-hybrid density functional belonging to the quadratic-integrand double-hybrid model to calculate association energies (E) and three-body effects (3E) arising from intermolecular interactions in weakly bound supramolecular complexes (i.e., the dataset 3B-69). The model behaves very accurately for trimer association energies and is found to outperform widely used density functional approximations while approaching the accuracy of more costly ab initio methods for three-body effects. The results are further improved when we add some specific corrections for the remaining dispersion interactions, D3(BJ) or VV10 for two-body effects and Axilrod-Teller-Muto for three-body effects, leading to marginal deviations (less than 1 kcal/mol for E and around 0.03–0.04 kcal/mol for 3E) with respect to benchmark results