where [α] ζ λ is the OR value obtained for the basis set aug-cc-pVζZ, A and n are fitting parameters, and [α] ∞ λ gives the OR value extrapolated to the CBS limit. In order to obtain a two point fitting for this system of equations, n must be fixed. Values of n were set to 3 for double/triple (DT) extrapolations and 5 for triple/quadruple (TQ) extrapolations, following the recommendation of Haghdani et al. The CBS values from the TQ extrapolations are utilized as the reference values in the comparisons, as described below. Basis sets with higher order angular momentum functions would provide results closer to the basis set limit, but we found that quadruple-ζ level was sufficient for the purposes of this study and it allows calculations on fairly large systems in a reasonable amount of time.