Figure 5.

K⁺ and Na⁺ coordination number for ions inside the filter. The atoms coordinating K⁺ and Na⁺ ions were calculated by collecting the data from all the umbrella-sampling simulations. Oxygen atoms were considered part of the coordination shell if they were <2.8 Å from a Na⁺ ion, and <3.2 Å from a K⁺ ion.