Nuclear quantum effects at the liquid/vapor interface from neural-network based path integral molecular dynamics...

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Materials Science

Background:

• Nuclear quantum effects (NQEs) are known to influence bulk water properties.
• The impact of NQEs on the liquid-vapor interface of water is not well understood.
• Accurate simulation of interfacial phenomena requires understanding all contributing factors.

Purpose of the Study:

• To investigate the role of NQEs at the liquid-vapor interface of water.
• To quantify the effect of NQEs on surface tension and critical point properties.
• To explore alterations in interfacial water molecule orientation due to NQEs.

Main Methods:

• Utilized machine-learned neural network potentials trained on ab initio data.
• Performed large-scale path-integral molecular dynamics simulations.
• Employed the RPBE-D3 level of theory for calculations.

Main Results:

• NQEs were found to marginally increase surface tension.
• The critical point of water was shifted to higher temperatures due to NQEs.
• Significant alterations in the orientational preferences of interfacial water molecules were observed.

Conclusions:

• This study provides the first direct quantification of NQEs on water's surface tension.
• Quantum fluctuations play a fundamental role in interfacial physics.
• Including NQEs is essential for accurate simulations of aqueous systems.