Ag(I) ion in liquid ammonia

Structural and dynamical properties of Ag+ in liquid ammonia have been evaluated on the basis of a molecular dynamics (MD) simulation by the ab initio quantum mechanical/molecular mechanical (QM/MM) method. The most important region, the first solvation shell, was treated by ab initio quantum mechanics at RHF (Restricted Hartree-Fock) level using double- plus polarization basis sets for Ag+ and ammonia, respectively. For the remaining region in the system newly constructed three-body corrected potential functions were used. The first solvation shell shows a tetrahedral structure with an Ag-N distance of 2.54 Angstrom, with no ammonia exchange process observable within a simulation time of 16 ps. The mean residence time (MRT) of ammonia molecules in the second solvation shell was determined as 12.7 ps. A force constant of 26 Nm(-1) was observed for the ion-ligand stretching frequency, indicating a more the stable solvate complex than for Ag+ in water. (C) 2004 Elsevier B.V. All rights reserved.