Quantum mechanical/molecular mechanical molecular dynamic simulation of zinc(II) ion in water

Abstract

The hydration structure of the Zn(II) ion has been studied by classical molecular dynamics (CMD) and quantum mechanical/molecular mechanical molecular dynamics (QM/MM-MD) simulations, using newly constructed ab initio two-body potentials and a three-body correction function. The average first-shell hydration structure is a 6-coordinate octahedron, and the structure parameters obtained by the QM/MM-MD simulation are in reasonable agreement with the experimental values. The first-shell angular distribution functions show a satisfactory consistency for both simulations, suggesting that the classical potential functions well describe the O–Zn–O angular distortion in the CMD simulation, while the quantum mechanical treatment of the Zn(II) ion and its first hydration shell in the QM/MM-MD simulation increases the tilting probability of the coordinating H 2O molecules. Dynamic properties such as vibrational and rotational motions of water molecules were evaluated using velocity autocorrelation functions (VACFs).