Development of Multiscale Force Field for Actinide (An³⁺) Solutions

Area of Science:

• Computational Chemistry
• Materials Science
• Nuclear Chemistry

Background:

• Accurate modeling of actinide solutions is crucial for nuclear waste management and remediation.
• Existing force fields struggle to capture the complex interactions of trivalent actinide cations (An³⁺) in aqueous environments.

Purpose of the Study:

• To develop a novel multiscale force field for aqueous trivalent actinide cations (An³⁺).
• To enhance simulation efficiency and accuracy in studying actinide chemistry.

Main Methods:

• Utilized a 12-6-4 Lennard-Jones potential with ion-induced dipole interactions.
• Employed the meta-multilinear interpolation parametrization (meta-MIP) algorithm for parameter optimization.
• Incorporated a polar coarse-grained (CG) water model (PW32) for increased efficiency compared to all-atom (AA) models.

Main Results:

• The developed force field accurately reproduces experimental ion-oxygen distances (IOD), coordination numbers (CN), and hydration free energies (HFE) for An³⁺.
• Demonstrated high transferability of the force field to predict An³⁺ permeability through graphene oxide filters using OPLS-AA.
• Reinvestigated hydration shell structure, water exchange dynamics, and ionic radii of An³⁺.

Conclusions:

• The new multiscale force field offers a computationally efficient and accurate approach for simulating actinide aqueous solutions.
• This FF is transferable and holds significant promise for advancing research in actinide chemistry and environmental applications.