Many-Body Potentials for Aqueous Be²⁺ Derived from ab Initio Calculations

Area of Science:

• Computational chemistry
• Physical chemistry
• Theoretical chemistry

Background:

• Accurate modeling of ion-solvation interactions is crucial for understanding chemical processes.
• Existing two-body potentials for beryllium ions (Be2+) in water have limitations in describing solvation structure and dynamics.

Purpose of the Study:

• To develop and validate an effective three-body potential for the aqueous Be2+ ion.
• To investigate the structural and dynamic properties of Be2+ hydration shells.
• To elucidate the mechanism and energetics of water exchange in Be2+ solvation shells.

Main Methods:

• High-level ab initio cluster calculations to construct the three-body potential.
• Molecular dynamics simulations of gas-phase ion-water clusters and bulk liquid.
• Analysis of radial and angular distribution functions for solvation shells.
• Calculation of power spectra for vibrational analysis.
• Computation of the potential of mean force for water exchange.

Main Results:

• The new three-body potential accurately reproduces the structures of the first and second solvation shells of Be2+.
• Vibrational spectra derived from simulations show good agreement with experimental data.
• The calculated energy barrier for water exchange shows improved agreement with experimental values compared to two-body potentials.
• Solvation structure analysis near the transition state supports an associative mechanism for water exchange.

Conclusions:

• The developed three-body potential provides a significant advancement in accurately describing the aqueous Be2+ ion.
• This improved potential enables more reliable simulations of ion-water interactions and chemical dynamics.
• The findings offer insights into the solvation behavior and water exchange processes of divalent metal ions.