In contrast, vibrational methods such as Raman spectroscopy do not suffer from these pitfalls. Raman spectroscopy can be used to interrogate a wide variety of samples with little preparation, including fibrils in solution, gels, and fibril films. Data acquisition is relatively fast and robust. In addition, Raman spectroscopy can be used to quantify the distributions of peptide bond and side chain dihedral angles in amyloid fibrils. Similarly, polarized Raman measurements can be used to determine the relative orientation of chemical bonds and functional groups in fibrils. Thus, the conformational sensitivity of Raman spectral features enables the facile differentiation of fibril polymorphs, as well as the ability to robustly monitor the structural evolution of oligomeric precursors that aggregate into fibrils. However, despite its versatility and structural sensitivity, Raman spectroscopy is generally considered to be a "lowresolution" characterization method in the broader amyloid community. One reason for this is because Raman spectroscopy has generally only been used to qualitatively evaluate fibril secondary structures rather than determining threedimensional models like ssNMR. We believe, however, that structural parameters measured using Raman spectroscopy (vide supra) can in fact be harnessed to determine detailed molecular-level structural models of amyloid fibrils. We recognize that this can be accomplished by taking inspiration from ssNMR, in which experimentally measured distances and dihedral angles are used as constraints in energy minimization procedures performed on structural models of amyloid fibrils using molecular dynamics (MD) simulations. To test this idea, we investigated the molecular structures of three fibril polymorphs prepared from amylin 20-29 and amyloid-β 25-35 (Aβ 25-35 ) peptides. Amylin 20-29 , de-rives from residues 20 -29 of the 37-amino acid amylin peptide, which forms fibrils implicated in the pathology of Type II Diabetes. . Amyloid-β 25-35 (Aβ 25-35 ) derives from residues 25 -35 of the 40-42 residue long Aβ peptide. Fibrils formed from Aβ compose extracellular plaques that have been implicated in the pathology associated with Alzheimer's disease and Cerebral Amyloid Angiopathy.