Fig. 3: OLAC layer properties investigated with XRR.

XRR curves obtained on (a) magnetite (001) and (b) magnetite (111) before and after OLAC dosing (10⁻⁶ mbar, 60 min). The gray data points and solid lines depict the respective clean surface XRR data and fit, while data points and fit of the OLAC covered surfaces are shown in black and red, respectively. Curves shifted vertically for clarification. Insets: Electron density profiles as a function of the distance perpendicular to the surface z. Experimentally calculated from the XRR fit after OLAC (red line) and estimated for individual components, i.e., magnetite (dashed blue), OLAC (dashed gray), and total (solid black), from MD simulations using the Density Profile Tool as discussed in the main text.