Solvation Structure and Dynamics of Ni(2+)(aq) from First Principles

The aqueous solution of Ni(2+) was investigated using first principles molecular dynamics (FPMD) simulation based on periodic density-functional theory (DFT) calculations. The experimental structural parameters of the Ni(aq) complex are reproduced well by the simulation. An exchange event of the water molecule in the first solvation shell is observed, supporting the proposed dissociative mechanism of exchange. The calculated dynamic characteristics of the surrounding water molecules indicate too slow translational diffusion in comparison to experimental results, in agreement with other FPMD studies employing a similar level of theory. We also find that the reorientational dynamics of water are an order of magnitude slower as compared to experimental data. On the other hand, the angular momentum dynamics are in better agreement with the experimental data than the previously reported results from MD simulations employing empirical force fields. The obtained MD trajectory can supply accurate structures for the calculation of magnetic properties.