The influence of quantum forces on molecular dynamics simulation results for hydrated aluminium(III)

Dynamic properties of hydrated aluminium(III) ion have been investigated by ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations at Hartree-Fock level including only the first or first plus second hydration shell into the QM region. The octahedral Al-O frequencies and ligand exchange processes between second shell and bulk have been evaluated. The results show that quantum effects play a non-negligible role also in the interaction of first and second shell and that inclusion of the latter into the QM region improves the values of sensitive dynamical data.