Thermophysical properties of water using reactive force fields.

Area of Science:

• Computational chemistry
• Materials science
• Physical chemistry

Background:

• Water's importance drives computational model development.
• ReaxFF force fields offer molecular flexibility, polarization, and reactivity for aqueous systems.
• Detailed evaluation of ReaxFF for general water properties is needed.

Purpose of the Study:

• To comprehensively benchmark two ReaxFF force fields (water-2017 and CHON-2017_weak) for modeling water.
• To assess their accuracy in predicting various thermophysical properties.

Main Methods:

• Benchmarking ReaxFF force fields against experimental data for water.
• Evaluating structural, electrostatic, vibrational, thermodynamic, coexistence, and transport properties.
• Testing at ambient conditions (300 K, 0.997 g cm⁻³) and along the 1 bar isobar.

Main Results:

• CHON-2017_weak generally predicted more accurate thermophysical properties than water-2017.
• Specific areas for improvement identified include dipole moment to quadrupole moment ratio and self-diffusion coefficient.
• Gas phase vibrational frequencies require refinement to enhance liquid water vibrational properties.

Conclusions:

• CHON-2017_weak is a more accurate ReaxFF model for general water properties than water-2017.
• Recommendations provided for improving ReaxFF force fields for water simulations.
• Further refinement is necessary for accurate modeling of water's complex behavior.