Proton mobility in aqueous systems: combining ab initio accuracy with millisecond timescales

Area of Science:

• Computational chemistry
• Physical chemistry
• Materials science

Background:

• Proton transport in aqueous systems is crucial for many chemical and biological processes.
• Accurately simulating proton dynamics in liquid water presents significant challenges due to multiscale phenomena.

Purpose of the Study:

• To develop and apply a multiscale simulation approach for accurate proton transport modeling in liquid water.
• To bridge the gap between ab initio accuracy and longer time scales relevant to diffusion dynamics.

Main Methods:

• Combining ab initio molecular dynamics (AIMD) simulations with force-field ensemble averaging.
• Incorporating kinetic Monte Carlo (kMC) simulations to extend the time scale.
• Capturing femtosecond dielectric relaxation dynamics of the hydrogen bonding network.

Main Results:

• Achieved ab initio accuracy in simulating proton transport.
• Successfully integrated femtosecond dynamics with millisecond diffusion processes.
• Developed a robust multiscale framework for aqueous proton dynamics.

Conclusions:

• The multiscale simulation approach provides unprecedented accuracy for proton transport in liquid water.
• This method enables the study of proton diffusion dynamics over biologically and chemically relevant time scales.
• The approach offers a powerful tool for investigating complex proton transfer mechanisms in condensed phases.