Given the importance of accurate polarizability calculations to many chemical applications, coupled with the need for efficiency when calculating the properties of sets of molecules or large oligomers, we present a benchmark study examining possible calculation methods for polarizable materials. We first investigate the accuracy of highly-efficient semi-empirical tight-binding method GFN2-xTB, and the popular D4 dispersion model, comparing its predicted additive polarizabilities to ωB97X-D results for a subset of PubChemQC and a compiled benchmark set of molecules spanning polarizabilities from approximately 3-600 Å^3, with a few compounds in the range of approximately 1200-1400 Å^3. Although we find GFN2 to have large errors with polarizability calculations, on large oligomers it would appear a quadratic correction factor can remedy this. We also compare the accuracy of DFT polarizability calculations run using basis sets of varying size and level of augmentation, determining that a non-augmented basis set may be used for highly polarizable species in conjunction with a linear correction factor to achieve accuracy extremely close to that of aug-cc-pVTZ.
Evaluating Fast Methods for Static Polarizabilities on Extended Conjugated Oligomers
