Ab Initio Simulation of Liquid Water without Artificial High Temperature

Area of Science:

• Computational chemistry
• Materials science
• Physical chemistry

Background:

• Accurate simulation of water structure and dynamics is vital for desalination, ion separation, electrocatalysis, and biochemical processes.
• Existing ab initio molecular dynamics (AIMD) methods require artificial high temperatures (AHT) to mimic quantum effects in water, which is inadequate for multiphase systems.
• AHT can overestimate water dynamics at interfaces and in solutions due to phonon activation in other phases.

Purpose of the Study:

• To develop and validate a computational method for accurately simulating liquid water at ambient conditions without AHT.
• To assess the performance of the regularized SCAN (rSCAN) functional for modeling water structure and dynamics.
• To evaluate rSCAN's accuracy for hydration structures of various ions.

Main Methods:

• Utilized ab initio molecular dynamics (AIMD) simulations.
• Employed the regularized SCAN (rSCAN) functional.
• Compared simulation results with experimental data for liquid water and ion hydration structures.

Main Results:

• The rSCAN functional accurately captures the structure and dynamics of liquid water at ambient conditions, eliminating the need for AHT.
• rSCAN shows excellent agreement with experimental data for the hydration structures of alkali, alkali earth, and halide ions.
• The findings demonstrate rSCAN's capability to model aqueous systems effectively.

Conclusions:

• The rSCAN functional provides a versatile and accurate approach for simulating aqueous environments.
• rSCAN is a promising tool for ab initio simulations of chemical processes in water.
• This method overcomes limitations of AHT in modeling complex aqueous systems.