Here it should also be noted that due to the normalization to the number of surface atoms the values would be different when referring them to the number of surface Pt atoms, but the trend would not change. As an example, comparing the total enthalpy gain for the formation of a Pt1Ag8/Pt4L unit cell of 9 x -0.26 eV = -2.34 eV with that for the formation of a Ag1L/Pt4L unit cell (9 x -0.30 eV = -2.70 eV), the insertion of a Pt atom (from a bulk reservoir) into the Ag1L/Pt4L surface layer would cost 0.36 eV.