The situation changes, however, as soon as water dissociation is considered. According to our experimental results, we could confirm slight traces of OH remaining after the desorption of molecular water. In Figure , the PES calculated for OH adsorbed on InP(001) 2×2-2D-2H (left) and 2×2-2D-1H (right) is shown. Here the adsorption energy is calculated with respect to molecular water, and is obtained as