Counterpoise correction from a practical perspective: is the result worth the cost?

Abstract

In the present study, we have examined the utility of counterpoise (CP) corrections, the zero-cost geometric counterpoise (gCP) correction, and the double-ζ vDZP basis set, in representative examples of computational chemistry investigations. The tests include reaction energies and barriers in mechanisms of catalysis, and binding of substrates with enzyme active sites. Drawbacks of the CP approach include: it is more costly than calculations with the same basis set without applying CP corrections, multiple computations may be required where a single species is used in multiple instances, and it is only applicable to intermolecular interactions. In comparison, using gCP or vDZP is less costly. Their overall accuracy is comparable to CP, although the three approaches show variable performances for different systems. Thus, the use of a large basis set remains more consistent in obtaining results that are closer to the basis-set limit. Where the computational cost poses a challenge, the use of gCP or vDZP would be more advantageous than CP in terms of cost and simplicity.