Density and Compressibility of Liquid Water and Ice from First-Principles Simulations with Hybrid Functionals.
We determined the equilibrium density and compressibility of water and ice from first-principles molecular dynamics simulations using gradient-corrected (PBE) and hybrid (PBE0) functionals. Both functionals predicted the density of ice to be larger than that of water, by 15 (PBE) and 35% (PBE0). The PBE0 functional yielded a lower density of both ice and water with respect to PBE, leading to better agreement with experiment for ice but not for liquid water. Approximate inclusion of dispersion interactions on computed molecular-dynamics trajectories led to a substantial improvement of the PBE0 results for the density of liquid water, which, however, resulted to be slightly lower than that of ice.
†Institute for Molecular Engineering, The University of Chicago, 5747 South Ellis Avenue, Chicago, Illinois 60637, United States.
Alex P
AP
Gaiduk
‡Department of Computer Science, University of California, Davis, One Shields Avenue, Davis, California 95616, United States.
François
F
Gygi
†Institute for Molecular Engineering, The University of Chicago, 5747 South Ellis Avenue, Chicago, Illinois 60637, United States.
Giulia
G
Galli
PBE0; ab initio molecular dynamics; compressibility; equilibrium density; hybrid functionals; ice; water