To aid in interpreting and assigning these features, we performed TB calculations on a model β-sheet system (Figures and; see Computational Section for details). We also compared our data with published low-frequency Raman spectra of poly-alanine and poly-glycine tions (β-poly-ala and β-poly-gly, respectively), as well as with inelastic neutron scattering data for proteins and amyloid fibrils. Inelastic neutron scattering is particularly useful for confirming assignments of bands arising from vibrational motions involving large displacements of hydrogen atoms, particularly from aliphatic groups. 101