Table 2.

The main wavenumbers involved in each of the four brain tumour subtypes vs. control classifications, with tentative biological assignments.

Approximate Wavenumbers (cm−1)	Tentative Biological Assignments	Vibrational Modes
1012	Carbohydrate	C-O stretch
1030	Glycogen	C-O and C-C stretch, C-OH deformation
1045	DNA and RNA	symmetric ${\mathrm{PO}}_2^{-}$ stretch
1050	Carbohydrate/Glycogen	C-O-C stretching and bending
1050–1100	DNA and RNA	Symmetric ${\mathrm{PO}}_2^{-}$ stretch
1240–1310	Amide III of Proteins	N-H in plane bend, C-N stretch
1245	Phosphodiesters	Asymmetric ${\mathrm{PO}}_2^{-}$ stretch
1340	Phospholipids	CH2 wagging
1400	Lipids/Proteins	CH3 bending
1470	Lipids	CH2 scissoring
1500–1600	Amide II of Proteins	N-H bending, C-N stretching
1600–1700	Amide I of Proteins	C=O and C-N stretch, N-H bending
1750	Lipids	C=O stretching