Phase Diagram of a Deep Potential Water Model

作     者：Linfeng Zhang Han Wang Roberto Car Weinan E 

作者机构：Department of Mathematics and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA and Beijing Institute of Big Data Research Beijing 100871 People’s Republic of China 

出 版 物：《Physical Review Letters》 (Phys Rev Lett)

年 卷 期：2021年第126卷第23期

页      面：236001-236001页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：Beijing Academy of Artificial Intelligence Office of Naval Research, ONR, (N00014-13-1-0338) Office of Naval Research, ONR U.S. Department of Energy, USDOE, (DE-SC0019394) U.S. Department of Energy, USDOE National Natural Science Foundation of China, NSFC, (11871110) National Natural Science Foundation of China, NSFC 

主　　题：Classical statistical mechanics First order phase transitions Interatomic & molecular potentials Phase diagrams Potential energy surfaces Water First-principles calculations Machine learning Molecular dynamics 

摘      要：Using the Deep Potential methodology, we construct a model that reproduces accurately the potential energy surface of the SCAN approximation of density functional theory for water, from low temperature and pressure to about 2400 K and 50 GPa, excluding the vapor stability region. The computational efficiency of the model makes it possible to predict its phase diagram using molecular dynamics. Satisfactory overall agreement with experimental results is obtained. The fluid phases, molecular and ionic, and all the stable ice polymorphs, ordered and disordered, are predicted correctly, with the exception of ice III and XV that are stable in experiments, but metastable in the model. The evolution of the atomic dynamics upon heating, as ice VII transforms first into ice VII′′ and then into an ionic fluid, reveals that molecular dissociation and breaking of the ice rules coexist with strong covalent fluctuations, explaining why only partial ionization was inferred in experiments.