<i>Ab initio</i> MD simulation systems.

<p>Each system consists of 10 lipids (top: DPhPC and bottom: DOPC), 418 water molecules for DPhPC-1 and DPhPC-2 or 358 water molecules for both DOPC-1 and DOPC-2 water molecules, and one excess proton. Water molecules and the hydrocarbon tails are rendered in sticks. Oxygen is in red, hydrogen in white, carbon in green, nitrogen in blue and phosphorus in yellow. Phosphate groups and the hydronium are depicted as spheres. The protonated phosphate group is highlighted in blue (DPhPC-1, DOPC-1). The interfacial hydronium is highlighted in green (DPhPC-2, DOPC-2).