MOLECULAR-DYNAMICS SIMULATIONS OF A POTASSIUM-ION AND AN IODIDE-ION IN LIQUID-AMMONIA

The systems consisting of one K+ with 215 ammonia and one I- with 215 ammonia molecules have been investigated by molecular dynamics simulat ions at an average temperature of 240 K, using a flexible ammonia mode l. K+-ammonia and I--ammonia pair potentials were constructed from ab initio calculations with basis set superposition error (BSSE) correcti on. Eventual non-additivity of the K+-ammonia potential has been also examined. Structural properties of the solutions were investigated thr ough radial distribution functions (RDFs) and their running integratio n numbers, leading to coordination numbers of 8.7 and 12-15 for K+ and I-, respectively. Velocity autocorrelation functions and their Fourie r transforms, describing the dynamical properties of the solutions, ar e in good agreement with available theoretical and experimental data. (C) 1997 Elsevier Science B.V.