Ab initio molecular dynamics simulations of Aluminum solvation

TL;DR

This study uses ab initio molecular dynamics to investigate aluminum ion solvation in water, revealing stable complexes, polarization effects, and hydration structures consistent with experimental observations.

Contribution

First ab initio molecular dynamics simulation of aluminum solvation, detailing stable complexes and hydration structures at finite temperature.

Findings

Hexa-hydrate aluminum ion forms a stable complex.

Hydrated water molecules exhibit high polarization (5.02 Debye).

Deprotonated complex evolves into tetra-coordinated aluminate with hydrogen bonding.

Abstract

The solvation of Al and its hydrolyzed species in water clusters has been studied by means of ab initio molecular dynamics simulations. The hexa-hydrate aluminum ion formed a stable complex in the finite temperature cluster simulation of one aluminum ion and 16 waters. The average dipole moment of strongly polarized hydrated water molecules in the first solvation shell of the hexa-hydrate aluminum ion was found to be 5.02 Debye. The deprotonated hexa-hydrate complex evolves into a tetra-coordinated aluminate ion with two water molecules in the second solvation shell forming hydrogen bonds to the hydroxyl groups in agreement with the observed coordination.