Density functional simulations of condensed phase water are typically inaccurate, due to the inaccuracies of approximate functionals. A recent breakthrough showed that the SCAN approximation can yield chemical accuracy for pure water in all its phases, but only when its density is corrected. This is a crucial step toward first-principles biosimulations. However, weak dispersion forces are ubiquitous and play a key role in noncovalent interactions among biomolecules, but are not included in the new approach. Moreover, na\"ive inclusion of dispersion in HF-SCAN ruins its high accuracy for pure water. Systematic application of the principles of density-corrected DFT yields a functional (HF-r2SCAN-DC4) which recovers and not only improves over HF-SCAN for pure water, but also captures vital noncovalent interactions in biomolecules, making it suitable for simulations of solutions.
@article{arxiv.2207.04169,
title = {Extending density functional theory with near chemical accuracy beyond pure water},
author = {Suhwan Song and Stefan Vuckovic and Youngsam Kim and Hayoung Yu and Eunji Sim and Kieron Burke},
journal= {arXiv preprint arXiv:2207.04169},
year = {2023}
}