Non-neutrality in a charged slit pore

Grand canonical Monte Carlo simulations are reported for restricted primitive model ions confined between two parallel charged walls. Single-ion insertion/deletion in the grand canonical ensemble simulation allows individual ions inside the slit pore to equilibrate with an external solution. Due to the confinement effect, the net charge of the ions inside is less than that required to balance the wall charges. The residue charge increases with a narrower slit or a higher charge density on the walls. The ion distribution between the walls is reported and compared with the modified Gouy Chapman results.