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.

采用0.6 kcal/mol/Ų的软简谐势对钠离子（Na+）与钾离子（K+）进行拉取操作，拉取步长Δλ为1 Å，该势函数的极小值点位于λ位置。拉取序列初始时刻，λ以模拟体系的质心z=0为中心。当λ以Δλ递增时，弛豫阶段τ内钠离子与钾离子的空间坐标不受约束。弛豫阶段τ结束后离子的z坐标列于下表，表中多组数值对应模拟中观测到的不同z坐标。图3展示了所有λ取值下，每种离子的不同z坐标出现频率的直方图。