Initially we modelled a single TEMPO molecule on a graphite surface, which has many possible binding geometries . The process of identifying preferred adsorption sites was therefore divided into two stages. First, we modelled a single TEMPO molecule 'scanned' across the graphite surface in a series of 1000 steps with different locations and orientations using a GGA + van der Waals functional (Figure ) . The strongestbinding configurations from this process with the corresponding binding energies are shown in Figure . This reveals that there are four favoured configurations corresponding to four energy minima. We find that the three most stable structures (1-3) correspond to geometries with upwards facing NO groups, with a slight preference for a tilted orientation. The two strongest binding configurations (1 and 2) correspond to TEMPOgraphite binding energies of approximately 0.6 eV, while the third and fourth minima (3 and 4) have a weaker binding energy of 0.4 eV. Simulations were also carried with the more conventional GGA functional as shown in Figures (the difference between binding energies obtained using vdW and GGA functionals is approximately 0.2 eV).