The G mode of graphite, E2g symmetry, is a mode (see Fig. in Ferrari and Robertson) that "does not require the presence of sixfold rings, and so it occurs at all sp 2 sites, not only those in rings. It always lies in the range 1500-1630 cm -1 , as it does in aromatic and olefinic molecules" (Ferrari and Robertson, mentioning Lin-Vien et al., 1991). D peak, about 1355 cm -1 , is due to a breathing mode with A1g symmetry, and the phonons which are involved are those close to the K zone boundary. "This mode is forbidden in perfect graphite and only becomes active in the presence of disorder. The D mode is dispersive; it varies with photon excitation energy, even when the G peak is not dispersive" (Ferrari and Robertson and references therein). Please, consider the further discussion in Ferrari and