SOLVATED ION DYNAMICS IN THE WATER-FORMAMIDE MIXTURES USING MOLECULAR-DYNAMICS SIMULATIONS

Molecular dynamics computer simulations have been performed for Na+-wa ter-formamide mixtures over the whole concentration range of the mixed solvent. It is shown that the Na+ cation is preferentially solvated b y formamide even if only small amounts of formamide are present in the mixture. Specific cation solvent shell formation leads to a drastic c hange of the ion microdynamics in the mixture compared to pure solvent s. A possibility of extension of the molecular theory of limiting ioni c mobility to mixed solvents was tested and could not be confirmed by the simulation. (C) 1997 American Institute of Physics. [S0021-9606(97 )52041-1].