Model for excess electron transport in dense heavy non-polar fluids

Abstract

The main features of the experimental results on excess electron transport are analysed. These features suggest a simple model: the excess electron is localised on one atom (or molecule) and its transport is due to a thermally assisted hopping. The results of a molecular dynamics simulation of the model are presented. Analogy between the drift velocity vd and the sound velocity vs leads to a general expression for vd including density, temperature, electric field and mass effects. The electron-atom interaction potentials Phi deduced from the field and density effects are in good agreement too. Application of the general expression at densities lower than the critical one shows that the thermally assisted hopping plays a decreasing role at decreasing densities. This means that the lifetime duration of the 'negative ion' becomes shorter than the mean time interval between two efficient collisions. The authors do not notice any aspect of the drift velocity data in dense heavy non-polar fluids disagreeing with the consequences of the model.