As surface coverage on (110) increases, we consider surfaces that have all or all but one of a single site type filled. In this limit, LB sites are the only ones that still have more favorable adsorption than the bulk. If all but one LB site are filled (see Fig. ), ∆∆e When all H sites are occupied, the Pu ridges are pulled equally towards the hydrogen on either side and so cannot move to stabilize adsorbates in one valley without destabilizing adsorbates in the other. When all fcc sites are occupied, each hydrogen will be within 2 Å of another, suggesting that hydrogen-hydrogen repulsion raises the energy of these configurations. Starting from an LB3 configuration, adding a hydrogen to an SB or H site results in a positive ∆∆e, while adding one to an fcc site results in a negative ∆∆e. As a result, we next consider the adsorption energy as a function of surface coverage considering only the LB and fcc sites. As the number of vacant LB sites decreases, there is a steep increase in adsorbtion energy.