Z-Coordinates (Å) for Stable Positions for Na⁺ and K⁺ Ions After Each Pulling Step (Δλ = 1 Å).

Na+ and K+ ions were pulled in increments (Δλ) of 1 Å using a soft harmonic potential of 0.6 kcal/mol/Å2 that has its minimum value at λ. At the start of the pulling sequence λ is centered at the center of mass of the simulation system, z = 0. As λ is incremented by Δλ, the spatial coordinates of the Na+ and K+ ions are unconstrained during the relaxation period τ. The z-coordinate of the ions at the end of τ is shown in the Table. Multiple values in the Table reflect the different z-coordinates observed in the simulations. A histogram of the frequency of occurrence of the different values for z for each ion at all values of λ is shown in Figure 3.