We then examined the overpolarization using B3LYP/aug-cc-pV(T+d)Z, a combination of a widely used density functional method and widely used augmented basis set. When using no implicit solvent (i.e., in gas phase), this method/basis set combination yields a slope estimate of 1.023 with a 95% CI of [1.004, 1.037] (Figure ). This indicates that there is a small amount of overpolarization relative to experiment inherent to this method/basis set, but that it is ~4 times smaller than the overpolarization of HF/6-31G* or HF/aug-cc-pV(T+d)Z.