where E(Pt 3 Ge x +slab) is the energy of the supported cluster after losing one Pt atom, E(Pt+slab) is the energy of a Pt atom supported on MgO on the most stable landing site, E(slab) for the energy of the pristine relaxed MgO(100) surface, E(Pt 4 Ge x-1 +slab) is the energy of the supported cluster after losing one Ge atom, and E(Ge+slab) is the energy of a Ge atom supported on MgO.