where E surf ace+radical is the total energy of the 6ZGNRH surface and the adsorbed radical. E radical and E surf ace are the total energy of the isolated radical and pristine 6ZGNRH surface. E CC is the counterpoise correction used to remove the basis set superposition error (BSSE). BSSE arises due to differences in basis set dimensions for the complete system (surface+radical) and the isolated surface and radical systems. This results in unphysical energy lowering of the system which can be corrected by the counterpoise method 68-70 using ghost atoms,