Hydration structure and water exchange dynamics of Na(I)ion in aqueous solution

Abstract

The hydration structure and water exchange dynamics in the first hydration shell for Na(I) in water are studied by molecular dynamics simulation. The structure of the hydrated ion is reported in terms of radial distribution functions, coordination numbers, and angular distributions. The average first-shell hydration structure is a 5.6, in agreement with experimental results. The classical umbrella-sampling molecular dynamic simulations was employed to investigate the water exchange reaction around the Na(I) ion in water. The water exchange mechanism proceeds via the I_d mechanism with the water exchange rate constant of 3.42 x 10¹¹ s^-1 at 298 K, estimated by the transition state theory assuming a transmission coefficient of unity.