Structure, Dynamics, and Spectral Diffusion of Water from First-Principles Molecular Dynamics

We have carried out first-principles BornOppenheimer molecular dynamics (BOMD) simulations of heavy water using density functional theory in conjunction with either empirical van der Waals (vdW) corrections or semilocal (van der Waals) exchange and correlation functionals. Specifically, gradient-corrected density functionals (BLYP), semiempirical vdW methods (BLYP-D2, BLYP-D3, PBE-D3, revPBE-D3), and vdW density functionals (DRSLL-PBE, DRSLL-optB88) are applied to evaluate their accuracy in describing the hydrogen-bonded network of heavy water. Ab initio trajectories are used to calculate structural and dynamical properties, with special emphasis on vibrational spectral diffusion and hydrogen bond dynamics. Our results show that inclusion of vdW interactions in DFT-GGA significantly affects the structure of liquid water and results in a faster diffusion. The combination of BLYP and revPBE functionals with the semiempirical vdW method of Grimme et al. [J. Chem. Phys. 2010, 132, 154104] and modified B88 functionals with the semilocal correlation functional according to M. Dion et al. [Phys. Rev. Lett. 2004, 92, 246401] provide the best agreement with experiments.