Using reactive force fields to describe the thermophysical and reactive properties of water
DOI: 10.1063/10.0006233
Using reactive force fields to describe the thermophysical and reactive properties of water lead image
Water is a complex liquid exhibiting numerous thermodynamic and dynamic anomalies. Attempting to describe this ubiquitous liquid accurately has resulted in a variety of computational paradigms. Gittus and Bresme investigated the scope and limitations of reactive force fields (ReaxFF), specifically two models, in modelling the thermophysical properties of water.
Empirical force fields are successful in reproducing the structural, thermodynamic, and transport properties of liquid water over a broad range of temperatures and pressures. However, these traditional paradigms are unable to describe water’s reactivity.
“Most of these models cannot be used to investigate self-ionization processes in situ,” said Bresme. “We are interested in modeling nanomaterial water interfaces under external fields using computer simulations.”
ReaxFF models offer more computationally feasible routes to simulating chemical reactivity. The reactive force fields can accommodate simulations of hundreds of thousands of atoms on the nanosecond timescale using state-of-the-art supercomputers.
The researchers investigated two ReaxFF models, CHON-2017_weak and water-2017. Their results suggest the CHON-2017_weak model more accurately predicts the thermophysical properties of water.
Gittus and Bresme offer recommendations for improvements in both models, including dipole moment to quadrupole moment ratios, self-diffusion coefficients, and gas phase vibrational frequencies.
The authors hope their study will provide other researchers with data for a more informed choice of reactive force fields.
“We anticipate [this work] will contribute to developing more accurate reactive force fields for water, enabling the study of problems where water’s thermophysical properties and reactivity are essential,” said Bresme.
Source: “Thermophysical properties of water using reactive force fields,” by Oliver R. Gittus and Fernando Bresme, Journal of Chemical Physics (2021). The article can be accessed at https://doi.org/10.1063/5.0057868 .
