Benchmark Calculations of Noncovalent Interactions of Halogenated Molecules

We present a set of 40 noncovalent complexes of organic halides, halohydrides, and halogen molecules where the halogens participate in a Variety of interaction types. The set, named X40, covers electrostatic interactions, London dispersion, hydrogen bonds, halogen bonding, halogen-pi interactions, and stacking of halogenated aromatic molecules. Interaction energies at equilibrium geometries were calculated using a. composite CCSD(T)/CBS scheme where the CCSD(T) contribution is calculated using triple-zeta basis sets with diffuse functions on all atoms but hydrogen. For each complex, we also provide 10 points along the dissociation curve calculated at the CCSD(T)/CBS level. We use this accurate reference to assess the accuracy of selected post-HF methods.