Ab Initio QM/MM Simulation of Ag+ in 18.6% Aqueous Ammonia Solution:  Structure and Dynamics Investigations

Structure and dynamics investigations of Ag+ in 18.6% aqueous ammonia solution have been carried out by means of the ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulation method. The most important region, the first solvation shell, was treated by ab initio quantum mechanics at the Restricted Hartree−Fock (RHF) level using double-ζ plus polarization basis sets for ammonia and plus ECP for Ag+. For the remaining region in the system, newly constructed three-body corrected potential functions were used. The average composition of the first solvation shell was found to be [Ag(NH3)2(H2O)2.8]+. No ammonia exchange process was observed for the first solvation shell, whereas ligand exchange processes occurred with a very short mean residence time of 1.1 ps for the water ligands. No distinct second solvation shell was observed in this simulation.