DIFFUSIONAL CHARGING OF DROPS IN A WEAKLY IONIZED AQUEOUS AEROSOL

A mathematical model is developed to describe the diffusional charging of drops of water in a weakly charged aerosol. The model accounts the selectivity with which ions of different sign are absorbed by the surface of the drops as a result of different dependences of the activation energy for reactions involving the absorption of positive and negative ions on the electric potential jump DELTAphi congruent-to 0.25 V at the water-air interface. It is shown that the well-known empirical relation q = -rDELTAphi expressing the dependence of the charge of a drop q on its radius r follows from the model that is presented.