Table 2 Values of wavenumber and Raman shift indicative for the identification of bitumen32,33,34,35,36, which were defined in residues on archaeological samples 1–5 on the basis of FTIR and Raman spectroscopy respectively.
Values of Wavenumber or Raman Band Shift [cm–1] | Description of the Band Assignment |
|---|---|
Sample 1 | |
2920 | Asymmetric stretching vibrations ν (C–H) in CH2– group |
2850 | Symmetric stretching vibrations ν (C–H) in CH2– group |
1460 | Deformational vibrations in CH– group |
1363 | Deformational vibrations in CH– group |
1583 | Raman peak G (around 1600 cm−1), vibration within the aromatic ring in the graphene cluster |
Sample 2 | |
1570 | Raman peak G (around 1600 cm−1), vibration within the aromatic ring in a graphene-like cluster |
1360 | Raman peak D (around 1350 cm−1), vibration within the aromatic ring in the graphene cluster |
Sample 3 | |
2920 | Asymmetric stretching vibrations ν (C–H) in CH2– group |
2850 | Symmetric stretching vibrations ν (C–H) in CH2– group |
1460 | Deformational vibrations in CH– group |
1421 | Deformational vibrations in CH– group |
1585 | Raman peak G (around 1600 cm−1), vibration within the aromatic ring in the graphene cluster |
1360 | Raman peak D (around 1350 cm−1), vibration within the aromatic ring in the graphene cluster |
Sample 4 | |
2960 | Asymmetric stretching vibrations ν (C–H) in CH3– group |
2920 | Asymmetric stretching vibrations ν (C–H) in CH2– group |
2890 | Symmetric stretching vibrations ν (C–H) in CH3– group |
2850 | Symmetric stretching vibrations ν (C–H) in CH2– group |
1460 | Deformational vibrations in CH– group |
1367 | Deformational vibrations in CH– group |
Sample 5 | |
2920 | Asymmetric stretching vibrations ν (C–H) in CH2– group |
2850 | Symmetric stretching vibrations ν (C–H) in CH2– group |
1460 | Deformational vibrations in CH– group |
1423 | Deformational vibrations in CH– group |
