Revisiting the density-corrected SCAN calculations for neutral and aqueous systems

The evaluation of the energy functionals on the Hartree-Fock density is a way to mitigate the delocalization error of the semi-local density functionals- often called density correction. Recent works [1,2] have reported that the density-corrected SCAN meta-GGA (DC-SCAN) achieves the accuracy of the coupled cluster theory for water. However, in a more recent work[3], we have found that the density-corrected semi-local functionals improve the barrier heights of chemical reactions because of the cancellation of the functional- and density-driven error for energy. Motivated by this, we reassessed the DC-SCAN calculations for neutral and ionic water clusters. We find that the remarkable accuracy of DC-SCAN probably comes from the error cancellation, suggesting density-overcorrection rather than a correction from the Hartree- Fock density.

References

1] S. Dasgupta, E. Lambross, J. P. Perdew, and F. Paesani, Nat. Commun. 12 6359 (2021)

2] S. Dasgupta, C. Shahi, P. Bhetwal, J. P. Perdew, and F. Paesani, J. Chem. Theory Comput. 18, 4745 (2022)

3] A. Kaplan, C. Shahi, P. Bhetwal, R. K. Sah, and J. P. Perdew, (arxiv.2207.13509v2) (2022)