Fig. 7
The (1 × 1) OH overlayer and molecular water. a STM image after dosing 0.4 L on the almost fully-developed (1 × 3) overlayer in Fig. 7c. The sample is almost completely covered by undulating, bright lines in [010] direction, showing only a few gaps, where the (1 × 3) structure is still visible. The single, bright features are unidentified adsorbates (approx. 0.03 ML) from the residual gas. The inset shows the DFT model and TH simulation of the (1 × 1) OH overlayer, i.e., the full monolayer. Both equivalent adsorption sites (B1O1 and B2O2) in the unit cell are occupied, i.e., all surface oxygens are hydroxylated. b STM image after exposing the sample in panel a to 0.75 L water. The gaps in the undulating bright hydroxyl lines have closed. The diffuse, white patches are assigned to molecular water (see Fig. 2). STM parameters: T sample = 78 K, V sample = −0.8 V, I tunnel = 0.1 nA; fast scan direction is 18° clockwise from horizontal. All scale bars correspond to 3 nm
