Extending density functional theory with near chemical accuracy beyond pure water

Density functional simulations of condensed phase water are typically inaccurate due to 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 crucial for first-principles biosimulations. However, weak dispersion forces, vital for noncovalent interactions in biomolecules, are not included. Naïve inclusion of dispersion in HF-SCAN ruins its accuracy. This paper presents HF-r²SCAN-DC4, which improves upon HF-SCAN for pure water and captures noncovalent interactions in biomolecules, making it suitable for solution simulations.

Suhwan Song, Stefan Vuckovic, Youngsam Kim, Hayoung Yu, Eunji Sim, Kieron Burke