Equation of State of Water Based on SCAN Meta-GGA Density Functional

Based on the new developed SCAN meta-GGA and the widely used PBE-GGA functionals, ab initio molecular dynamics are performed on water. It is proved that, although SCAN meta-GGA is not as good as TIP4P/2005 model potential in describing the equation of state of water, it is much better than PBE-GGA, ST2 model potential, and ab initio trained neural network potentials. Moreover, SCAN meta-GGA predicts a first-order liquid-liquid transition from high- to low-density water at negative pressure, with the structure of them qualitatively consistent with experimental observations, and the spinodal point of high-denstiy water is very close to Speedy's stability limit line.