Raman spectra of virgin and damaged graphite edge planes

First-order Raman spectra of virgin and ion irradiated highly oriented pyrolytic graphite were performed along the basal and edge planes. Ion irradiation was performed in the low fluence regime (approximate to 10(12)-10(13) ions cm(-2)) using a 400 keV Ar+ beam in order to a introduce controlled amount of defects in the structure. Virgin edge Raman spectra reveal the presence of a 1351 cm(-1) structure (D*) shifted 10 cm(-1) away from the disorder induced D-line found upon irradiating or grinding the graphite surface. The 1351 cm(-1) D* structure is then considered as the feature coming from the rupture of the D-6h(4) space group symmetry. A comparison between D* and the classical 1360 cm(-1) D-line is discussed in terms of induced disorder. (C) 1997 Elsevier Science Ltd.