Assuming that monomers account for the majority of the flux to the surface 10 , we first model the electronic properties of single TEMPO monomers in gas phase and then adsorbed on graphite using a combination of DFT and the counterpoise method . As a first step, we explore two different orientations for two TEMPO molecules in gas phase (Figure ): parallel NO groups (denoted up-up) or anti-parallel (denoted up-down). Figure demonstrates that the latter is the most energetically favourable with an energy difference of approximately 0.10 eV. This is a result of the electrical dipole moments preferring an anti-aligned orientation, which forces the oxygen atoms in the two neighbouring TEMPO molecules into the up-down orientations (for more details see TEMPO-TEMPO gas phase simulations in the SI and Figures ).