Empirically Optimized One-Electron Pseudopotential for the Hydrated Electron: A Proof-of-Concept Study

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Quantum Mechanics

Background:

• Mixed quantum-classical molecular dynamics (MQCMD) simulations are crucial for studying the hydrated electron.
• Current methods often use one-electron pseudopotentials, which offer computational advantages but face scrutiny regarding accuracy.
• Pseudopotentials are typically fitted to *ab initio* calculations of electron-water interactions.

Purpose of the Study:

• To develop and validate an alternative approach for pseudopotential parameterization in hydrated electron simulations.
• To demonstrate a proof-of-concept for optimizing pseudopotentials against experimental properties.
• To improve the quantitative description of hydrated electron properties.

Main Methods:

• Developed a new pseudopotential based on the TBOpt model.
• Optimized pseudopotential parameters by fitting to key experimental properties of the hydrated electron.
• Employed mixed quantum-classical molecular dynamics simulations.

Main Results:

• The new empirically optimized pseudopotential accurately reproduces the hydrated electron's vertical detachment energy and radius of gyration.
• The model shows a significantly modified solvation structure compared to previous methods.
• Improved prediction of partial molar volume was observed.

Conclusions:

• Empirical optimization of pseudopotentials against experimental data is a viable alternative to *ab initio* fitting.
• This approach enhances the accuracy and predictive power of MQCMD simulations for the hydrated electron.
• The improved solvation structure offers deeper insights into electron-water interactions.