California Institute of Technology
Post Doctoral Scholar
Friday, November 22, 2019
We have developed a new generation of reactive force field (FF), RexPoN, which retains high level quantum mechanics (QM) accuracy for multiscale simulations of materials and energy systems with millions of atoms. All components of RexPoN FF are based entirely on QM with no empirical information.
In this talk, I will show the results of our RexPoN simulations for water system. It leads to very accurate properties of water ever predicted by any water model (e.g. ice melting point 273.3 K versus expr. 273.15 K). RexPoN accurately describes the first coordination shell and therefore the hydrogen bond (HB) network of liquid water, a problem that had challenged the community for decades. As a result, RexPoN established a revolutionary new paradigm for the structure of water that was never thought of before.
The puzzling anomalous properties of water are drastically enhanced in supercooled region. In particular, thermodynamic response functions show a power-law divergence in the properties near 228 K. Since the 1970’s, there have been numerous experiments and simulations attempting to understand the nature of these anomalies but there is no global consensus. I will report the results of our RexPoN simulations for deeply supercooled liquid water (down to 200 K) which provide a new description for the origin of anomalies in this region.
Our results show the ability of RexPoN FF for making significant breakthroughs in the design and discovery of new materials that are required to address the enormous problems in energy, economy, and environment.