We have studied the four different geometric configurations of TMM radical on 6ZGNRH surface. 6ZGNRH has three major adsorption sites (shown in Figure ), the hollow site which is the center of the hexagonal rings of ZGNR, the bridge site which is the center of the C-C bond of ZGNR and the top site which is the position of the carbon atom of ZGNR. TMM is deposited in four configurations on 6ZGNRH based on different adsorption sites. For simplicity, we have abbreviated the TMM adsorbed 6ZGNRH system as T6ZN-Gn, where T, 6ZN and Gn represent TMM radical, 6ZGNRH and n th geometric configuration of TMM respectively. In configuration 1 (T6ZN-G1), TMM is deposited on 6ZGNRH in such a way that the C1 carbon atom of TMM is on the top site and the other three carbon atoms (C2, C3 and C4) are on the hollow site. In T6ZN-G2, the C1 carbon atom of TMM is on the bridge site. In T6ZN-G3, the C1 carbon atom of TMM is on the hollow site and the other three carbon atoms (C2, C3 and C4) are on the bridge site. Similarly, in T6ZN-G4, the C1 carbon atom of TMM is on the hollow site and the C2, C3 and C4 are on the top site. For all the configurations, a starting perpendicular distance of 2.0 Å between 6ZGNRH and TMM is set for geometry optimization. We have optimized the TMM deposited 6ZGNRH using the semi-empirical dispersion correction scheme of Grimme DFT-D2, to take into account the effects of long-range van der Waals (vdW) interactions. The default numbers recommended by Grimme in the original discussion of his method were used for vdW radii and dispersion coefficients for carbon and hydrogen. TMM is physisorbed on 6ZGNRH in configurations T6ZN-G1, T6ZN-G2 and T6ZN-G3 while it is chemisorbed in configuration T6ZN-G4. Adsorption energy between the 6ZGNRH surface and adsorbed radical was calculated as follows: