Quantum effects in liquid water from an ab initio-based polarizable force field

Area of Science:

• Computational chemistry
• Physical chemistry
• Materials science

Background:

• Accurate simulation of liquid water properties is essential for various scientific disciplines.
• The TTM2.1-F force field is an ab initio-based model designed for simulating water.
• Understanding the role of quantum effects is key to improving simulation accuracy.

Purpose of the Study:

• To quantitatively assess the importance of quantum effects in liquid water simulations.
• To evaluate the accuracy of the TTM2.1-F polarizable force field.
• To investigate the temperature dependence of thermodynamic and dynamical properties.

Main Methods:

• Path-integral molecular dynamics (PIMD) and centroid molecular dynamics (CMD) were employed.
• Analysis focused on temperature-dependent thermodynamic and dynamical properties.
• Comparisons were made with empirical and other ab initio-based force fields.

Main Results:

• Quantum effects are significant even at elevated temperatures, necessitating their inclusion in simulations.
• The TTM2.1-F model provides an accurate description of liquid water properties.
• Nuclear quantization effects on the dielectric constant depend on electronic polarization treatment.
• Quantum tunneling appears to have a minor contribution to observed dynamical properties.

Conclusions:

• Quantum mechanical effects are vital for accurate simulations of liquid water.
• The TTM2.1-F force field demonstrates good performance in describing liquid water.
• Further research may be needed to fully elucidate the role of quantum tunneling in water dynamics.