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. Io n 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 intr oduce controlled amount of defects in the structure. Virgin edge Raman spectra reveal the presence of a 1351 cm(-1) structure (D) shifted 1 0 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) spac e 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.