"Key vibrational modes of various defects were analyzed for distinctive regions to create a new series of band assignments specifically tailored for chars produced at temperatures below 700 °C" . The researchers obtained a shoulder peak, about 1200 cm -1 , related to the vibrational modes for PAH structures, in particular of cycloheptane and larger ring systems. "The breathing modes of small PAHs (Naphthalene-pyrene scale) were found to be present between 1200 cm -1 and 1300 cm -1 as well as for larger ring systems (greater than coronene)". Moreover, Smith and coworkers consider "the valley commonly observed in Raman spectra and chars" consistent with the proposed models of disorder. For what is regarding the band between 1400 cm -1 and 1450 cm -1 , the researchers assigned it "to Kekulé dominated vibrational modes". The spectrum between 1480 cm -1 and 1550 cm -1 , that is the asymmetric G-band, is linked by Smith and coworkers "to coupling of breathing modes and asymmetric stretching caused by strained deformation within the PAH clusters and constriction of motion caused by oxygen inclusion" (Smith et al., 2016).