The S66 noncovalent interactions benchmark reconsidered using explicitly correlated methods near the basis set limit

TL;DR

This paper re-evaluates the S66 noncovalent interactions benchmark using advanced explicitly correlated methods near the basis set limit, providing insights into more accurate and efficient computational approaches.

Contribution

It demonstrates the effectiveness of combining CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets and extrapolation techniques for high-level corrections in noncovalent interaction calculations.

Findings

Post-MP2 high-level corrections are well-treated with the proposed methods.

Using sano-V{D,T}Z+ basis sets accelerates calculations with minimal accuracy loss.

Half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers a good accuracy-cost compromise.

Abstract

The S66 benchmark for noncovalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 "high-level corrections" are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66x8 problem set in particular, and for accurate calculations on noncovalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, while half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.