Exploring non-equilibrium molecular dynamics of mobile protons in the solid acid CsH₂PO₄ at the micrometer and...

Area of Science:

• Materials Science
• Computational Chemistry
• Solid-State Physics

Background:

• Proton dynamics in solid acids are crucial for energy applications.
• Simulating these dynamics at larger scales remains computationally challenging.

Purpose of the Study:

• To develop a multiscale method for simulating proton dynamics in CsH2PO4 at micrometer length scales.
• To enable the study of inhomogeneities and non-equilibrium processes in solid acids.

Main Methods:

• Developed the molecular dynamics/matrix propagation (MDM) method, a multiscale Markov model.
• Condensed molecular dynamics information into an M x M matrix, reducing complexity.
• Incorporated correlations between protonation states of neighboring sites.

Main Results:

• MDM method allows simulations at nanometer scales and millisecond timescales.
• Quantitative computation of atomistic features like mean square displacement and diffusion coefficient.
• Demonstrated application by simulating a non-equilibrium process in an 8 μm CsH2PO4 system.

Conclusions:

• The MDM method effectively simulates proton dynamics in CsH2PO4 at extended scales.
• This approach facilitates the study of complex proton transport phenomena in solid acids.
• The method conserves the Markov character while incorporating neighbor correlations.