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The present work reports a theoretical study of the infrared (IR) and Raman spectra of chemical structures that are useful for the description of the surface chemistry of carbon materials. There has been a recent demand in materials science and surface functionalization to couple organic entities with sp 2 carbon nanostructures. A slab model of single-layer graphene with its edges terminated by hydrogen atoms containing 82 atoms per unit cell was used in our study. The organic coupling agent, perfluorophenylazide (PFPA), was used according to a recent experiment [Liu, L.-H.; et al.et al. Nano Lett. 2010, 10, 3754]. Two ab initio DFT functionals, B3LYP and ωB97XD, were adopted to calculate the IR and Raman spectra. The computational approach was tested by comparing the calculated IR spectra to those obtained experimentally for various reference compounds. The vibrational features were probed before and after the reaction, and the changes, arising in both PFPA and graphene spectra as a result of the coupling, were identified. B3LYP gave better agreement with the experimental results than ωB97XD for frequency calculations. The stretch modes of the azide group, as well as the fingerprint feature of the CF 2 axial stretching vibrations, were used to probe the reaction, and the results were in good agreement with the experimental observations. Special attention was paid to the elucidation of the origins of the G-, D-, and D′-bands in the Raman spectra of graphene. Finally, the predicted assignments were employed to interpret the IR and Raman spectra obtained experimentally for functionalized graphenes.

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