Hydration of Li+ -ion in atom-bond electronegativity equalization method-7P water: a molecular dynamics simulation...

Area of Science:

• Computational Chemistry and Physics
• Physical Chemistry
• Materials Science

Background:

• Accurate modeling of ion-water interactions is crucial for understanding electrolyte behavior.
• Previous models often struggle to capture the dynamic and fluctuating nature of ionic hydration shells.
• The atom-bond electronegativity equalization method (ABEEM) offers a promising approach for developing flexible, charge-transferring potentials.

Purpose of the Study:

• To investigate the hydration properties of lithium ions (Li+) in aqueous solutions using molecular dynamics (MD) simulations.
• To evaluate the performance of newly developed ABEEM/molecular mechanics (MM) potentials for Li+-water and water-water interactions.
• To analyze the temperature-dependent structural, dynamic, and thermodynamic properties of Li+ hydration.

Main Methods:

• Employed molecular dynamics (MD) simulations over a wide temperature range (248–368 K).
• Utilized the ABEEM-7P water model, a flexible seven-site model with fluctuating charges.
• Incorporated a recently developed Li+-water interaction potential fitted to experimental and ab initio gas-phase data.

Main Results:

• The ABEEM/MM potentials successfully reproduced static, dynamic, and thermodynamic properties of Li+ hydration.
• Simulated radial distribution functions, diffusion coefficients, and residence times showed excellent agreement with experimental findings.
• The model accurately captured the fluctuating charges and short-range hydrogen bond interactions within the hydration shell.

Conclusions:

• The ABEEM/MM-based potentials are robust and reliable for simulating Li+ hydration in aqueous solutions.
• The developed model provides an accurate description of Li+ hydration properties across a broad temperature spectrum.
• This approach offers a significant advancement in modeling aqueous electrolyte systems.