IR spectral fingerprints of carbonyl groups in graphite oxide: a theoretical study

Non-empirical quantum chemical calculations of various possible fragments in the oxidized carbon layer of graphite oxide were carried out at the DFT level with the hybrid B3LYP functional and the extended double-zeta Gaussian basis set. These fragments contain the carbonyl groups as ketone, carboxyl and lactone functions, either free or hydrogenbonded to hydrating water molecules or closely arranged hydroxyl groups. Using the vibrational energy distribution analysis, the typical spectral ranges of C=O vibrations were identified within the fingerprint region of 1550–1800cm⁻¹ depending on the kind of the carbonyl group studied and its environment.