Focal-Point Analysis to Achieve Accurate CCSD(T) Data Set References for Static Polarizabilities

Static polarizability is an important ingredient for describing optical phenomena, intermolecular interactions, etc. It also offers a way to gauge the accuracy of the electronic structure methods. However, polarizability data sets that include a large variety of species with high-quality reference data are still lacking. In this work, we calibrate the reference data of two existing data sets, HR46 (Hickey and Rowley J. Phys. Chem. A 2014, 118, 3678-3687.) and T145 (Thakkar et al. Chem. Phys. Lett. 2015, 635, 257-261.), consisting of molecules with sizes up to 15 atoms. We apply the focal-point analysis (FPA) to the isotropic and anisotropic polarizability calculations, achieving the MP2 correlation contribution by the complete basis set (CBS) extrapolation of aug-cc-pCV[Q5]Z, augmented by the CCSD(T) correlation contribution from the CBS extrapolation of aug-cc-pV[XY]Z with [XY] = [Q5], [TQ], and [DT], respectively, to accommodate the computation to the system size. We conclude that our reference data are close to the CCSD(T)/aug-cc-pCV[Q5]Z quality, which are beneficial to the future assessment and benchmark studies of other electronic structure methods, in particular, density functional approximations.