A picture of near-equilibrium hydriding begins to emerge as we examine adsorption energetics on all three surfaces. On the (100) surface, the lowest energy sites are H sites, which are 1-2 k B T /H higher in energy than bulk O sites. Accordingly, the two-state model results suggest that the fraction of populated H sites will be comparable to the bulk absorption, O(10 -3 ). The (111) surface will have no substantial surface coverage since the lowest energy structures are all > 7 k B T /H higher in energy. On the (110) surface, adsorption in isolated LB sites is -15 k B T /H relative to the bulk, suggesting that some LB sites will always be filled. Even with the majority of LB sites filled the adsorption energy increases to only -3 k B T /H. The two-state model, in turn, shows that surface sites with -3 k B T adsorption energies will be only be 10% filled, though this picture is somewhat oversimplified. Regardless, LB sites, though few in number due to the high surface energy of the (110) surface, could serve as nucleation sites for equilibrium hydriding due to their high stability once occupied.