| Raman (405 nm excitation), three most intense peak shifts | 1156, 1359, 1527 cm⁻¹ |
|---|---|
| Raman (405 nm excitation), literature-based assignments | 1156 cm⁻¹ carotenoid ν2, in-phase C-C stretch of the conjugated polyene backbone, coupled with C-H in-plane bending; 1359 cm⁻¹ porphyrin ν4, symmetric pyrrole ring (“half-ring”) breathing stretch; 1527 cm⁻¹ carotenoid ν1 C=C stretch with possible overlapping porphyrin ν19/ν3 contribution |
| Raman (532 nm excitation), three most intense peak shifts | 1004, 1155, 1515 cm⁻¹ |
| Raman (532 nm excitation), peak shift | 1003 cm⁻¹ |
| Raman (532 nm excitation), literature-based assignments | 1004 cm⁻¹ carotenoid ν3, in-plane CH3 rocking mode of methyl groups on the polyene chain, coupled to C-C bonds; 1155 cm⁻¹ carotenoid ν2, in-phase C-C stretch of the conjugated polyene backbone, coupled with C-H in-plane bending; 1515 cm⁻¹ carotenoid ν1, in-phase C=C stretch of the conjugated polyene backbone |
| Raman (785 nm excitation), three most intense peak shifts | 1003, 1448, 1658 cm⁻¹ |
| Raman (785 nm excitation), literature-based assignments | 1003 cm⁻¹ phenylalanine symmetric ring-breathing mode; 1448 cm⁻¹ CH2/CH3 deformation, protein and lipid backbone; 1658 cm⁻¹ amide I, C=O stretch of the protein backbone |
George Devitt, Anna Crisford, Amber Cooper, Simon Lane, Callum Ellis, Amrit Mudher, Christopher Kipps, Sumeet Mahajan. “Multi-excitation Raman spectroscopy (MX-Raman) enhances Alzheimer’s disease class separability in human serum.” ChemRxiv (). https://doi.org/10.26434/chemrxiv.15007544/v1