Surface coverage was measured for the citrate molecules as a fraction of bound vs. total citrate, as well as for the surface itself, using the fraction of surface gold atoms that are within 3.5 Å of a citrate ion. In either case, the criterion for binding is similar. Gold atoms within 3.5 Å of any citrate atom are considered bound to a citrate, and citrate ions with an oxygen atom within 3.5 Å of gold are considered bound to the surface. The fraction of bound citrates (see Table ) appear to be highly curvature dependent, with planar (111) slabs exhibiting more bound citrate than the nanoparticles.