Figure 3. a) The optimized structure of 1 ML H2O + 0.5 ML H covered TiO2 surface from DFT calculation. Blue, green and red spheres represent Ti, O, and H atoms respectively. The bottom shows the electron density contours for the same structure as shown on top for electrons at 2.3 eV above the Fermi level. The adsorbates bound electrons are delocalized in clusters involving one OH group and two H atoms on two adjacent H2O molecules, which are indicated on top by white ellipsoids. b) The optimized structure and electron density contours at 1.3 eV for 1 ML H on TiO2. The electrons are delocalized in 1D-chains on H atoms along the bridging oxygen rows. These 1D chains represent the lowest energy wet electron structure found by theory. c) The correlation of the wet electron state energy for different coverages of H2O and H adsorbates with the number of dangling H atoms in each solvation cluster. The infinite dangling H atom number represents the structure in b). All structures in the observable energy range are associated with surface OH.