Evaluating Cost\nand Accuracy in Two-Point Complete\nBasis Set Extrapolation Schemes Using Efficient Diffuse Basis Sets

A widely used procedure for obtaining the complete basis\nset (CBS)\nlimit of an electronic structure method is to extrapolate results\nfrom a sequence of correlation-consistent basis sets. A recent study\nby Xi et al. [<i>J. Phys. Chem. A</i> <b>2024</b>, <i>128</i>, 3742−3749] trained two-point extrapolation schemes\nagainst a new extensive dataset using aug-cc-pV<i>X</i>Z\n(<i>X</i> = D, T, Q, 5, and 6) basis set pairs. Their results\nwere very promising, providing a significant improvement over previous\ntwo-point extrapolation schemes. The present work shows that equally\ngood results can be obtained at lower cost by using the smaller jun-cc-pV<i>X</i>Z or jul-cc-pV<i>X</i>Z basis sets, which contain\nfewer diffuse functions. Using the smaller jun and jul basis sets\nto extrapolate to the CBS limit provides a good compromise between\naccuracy and computational cost.