Figure 3: Data from the molecular dynamics simulations of mica in aqueous solution.
From: Water-induced correlation between single ions imaged at the solid–liquid interface
Three different starting configurations have been tested: with the cations randomly adsorbed (a), forming a row on mica (b) or a hexagon (c). The average hydration (open square), electrostatic (open triangles) and total (open circles) free energy of the adsorbed ions is given for each type of ion an each starting configuration (d). The data in d are extracted from the evolution of the hydration energy per adsorbed ion throughout the simulation. The error bars in d are 2 s.d. In e, a schematic depiction of the water surrounding adsorbed K+. A clear difference is visible between isolated ions or ions forming geometrical patterns where the location of shared water molecules is well defined. From MD simulations, the density of oxygen atoms of the water molecules is also shown. In the case of single ion, the value of the oxygen density is the radial average around the K+ ion. In the case of row of K+, the average oxygen density is obtained by considering a rectangle of 0.5 nm width aligned with the row of the ions and centred on them.
