A classical density functional theory for solvation across length scales

Bui, Anna T.; Cox, Stephen J.

Abstract

A central aim of multiscale modeling is to use results from the Schrödinger equation to predict phenomenology on length scales that far exceed those of typical molecular correlations. In this work, we present a new approach rooted in classical density functional theory (cDFT) that allows us to accurately describe the solvation of apolar solutes across length scales. Our approach builds on the Lum–Chandler–Weeks (LCW) theory of hydrophobicity [K. Lum et al., J. Phys. Chem. B 103, 4570 (1999)] by constructing a free energy functional that uses a slowly varying component of the density field as a reference. From a practical viewpoint, the theory we present is numerically simpler and generalizes to solutes with soft-core repulsion more easily than LCW theory. Furthermore, by assessing the local compressibility and its critical scaling behavior, we demonstrate that our LCW-style cDFT approach contains the physics of critical drying, which has been emphasized as an essential aspect of hydrophobicity by recent theories. As our approach is parameterized on the two-body direct correlation function of the uniform fluid and the liquid–vapor surface tension, it straightforwardly captures the temperature dependence of solvation. Moreover, we use our theory to describe solvation at a first-principles level on length scales that vastly exceed what is accessible to molecular simulations.

Citation

Bui, A. T., & Cox, S. J. (2024). A classical density functional theory for solvation across length scales. The Journal of Chemical Physics, 161(10), Article 104103. https://doi.org/10.1063/5.0223750

• Journal Article Type: Article
• Acceptance Date: Aug 14, 2024
• Online Publication Date: Sep 9, 2024
• Publication Date: Sep 14, 2024
• Deposit Date: Nov 20, 2024
• Publicly Available Date: Nov 20, 2024
• Journal: The Journal of Chemical Physics
• Print ISSN: 0021-9606
• Electronic ISSN: 1089-7690
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 161
• Issue: 10
• Article Number: 104103
• DOI: https://doi.org/10.1063/5.0223750
• Public URL: https://durham-repository.worktribe.com/output/3101624