  We perform ab initio molecular dynamics (AIMD) simulation of liquid water in
the canonical ensemble at ambient conditions using the SCAN meta-GGA functional
approximation, and carry out systematic comparisons with the results obtained
from the GGA-level PBE functional, and Tkatchenko-Scheffler van der Waals (vdW)
dispersion correction inclusive PBE functional. We analyze various properties
of liquid water including radial distribution functions, oxygen-oxygen-oxygen
triplet angular distribution, tetrahedrality, hydrogen bonds, diffusion
coefficients, ring statistics, density of states, band gaps, and dipole
moments. We find that the SCAN functional is generally more accurate than the
other two functionals for liquid water by not only capturing the
intermediate-range vdW interactions but also mitigating the overly strong
hydrogen bonds prescribed in PBE simulations. We also compare the results of
SCAN-based AIMD simulations in the canonical and isothermal-isobaric ensembles.
Our results suggest that SCAN provides a reliable description for most
structural, electronic, and dynamical properties in liquid water.
