Assessing the potential of zero charge in ab initio molecular dynamics simulations

Area of Science:

• Computational Electrochemistry
• Materials Science
• Physical Chemistry

Background:

• Accurate determination of the potential of zero free charge (PZFC) from ab initio molecular dynamics (AIMD) simulations is crucial for understanding electrochemical interfaces.
• Existing computational referencing strategies, such as the work-function (WF) and computational standard hydrogen electrode (cSHE), have inherent limitations impacting PZFC accuracy.

Purpose of the Study:

• To critically evaluate the limitations of current WF and cSHE methods for PZFC determination in AIMD simulations.
• To introduce and validate a novel revised work-function (revWF) approach for more robust PZFC calculations.
• To provide practical guidelines for computational PZFC evaluation and interpretation.

Main Methods:

• Comprehensive literature data analysis combined with new AIMD simulations.
• Comparative assessment of the work-function (WF) and computational standard hydrogen electrode (cSHE) referencing strategies.
• Development and application of the revised work-function (revWF) method.

Main Results:

• Both WF and cSHE methods exhibit intrinsic limitations: WF suffers from statistical uncertainty at the water/vacuum interface, while cSHE depends strongly on setup-specific inner reference energies.
• The proposed revWF approach effectively unifies the strengths of existing methods while mitigating their weaknesses.
• The revWF method demonstrates improved transferability and computational efficiency for PZFC determination.

Conclusions:

• The revWF approach provides a more robust and reliable reference scheme for AIMD simulations of electrochemical interfaces.
• This work offers practical guidelines for assessing computational PZFC values.
• The findings contribute to advancing the accuracy and efficiency of computational electrochemistry research.