MD simulations of Na atoms on H20


In this project, we modelled the surface of liquid water (snapshot at top-left) using Molecular Dynamics simulations (using the DL_POLY software package and the SPC/E force field). We then 'fired' Na atoms at the water surface to investigate how far the Na atoms would penetrate into the surface as a function of their velocity.


The main results are:

• Na atoms barely penetrate into the surface, only a small fraction of the Na atoms is below the depth of around 1 monolayer

• The kinetic energy of the Na atoms does not play a major role, but within the experimentally reasonably-achievable velocities (500 - 2000 m s-1), there is a small trend for faster Na atoms to penetrate a little deeper as expected

• While we have not modelled the production of Na+ cations and hydrated electrons (as we restricted our simulations to classical molecular dynamics simulations), these results nonetheless indicate that Na atom bombardement of liquid water should be an excellent route to produce surface hydrated electrons.