Fragment molecular orbital-based molecular dynamics (FMO-MD) simulations on hydrated Zn(II) ion

Recently, the method of fragment molecular orbital-based molecular dynamics (FMO-MD) was enhanced by including the three-body corrections (FMO3) [Y. Komeiji, Y. Mochizuki, T. Nakano, Chem. Phys. Lett. 484 (2010) 380]. This simulation protocol was applied to a droplet model consisting of a divalent zinc ion and 64 water molecules, in order to investigate the hydration structure in ab initio fashion. The first peak position of the Zn–O radial distribution function (RDF) was evaluated to be 2.05 Å at the FMO3-HF/6-31G level of theory, which was in agreement with an X-ray value of 2.06 ± 0.02 Å. The coordination number was evaluated to be 6, corresponding to an octahedral coordination.