The Raman structural constraints that we utilized can be determined by employing either non-polarized or polarized measurements. Thus, our approach does not inherently rely on aligned fibril samples or polarization measurements. However, more structurally-sensitive Raman spectroscopic markers need to be discovered to enable the determination of higher-resolution fibril models. There are several reports describing Raman spectroscopic markers that can be used to measure amino acid side chain dihedral angles. However, these apply to only a handful of amino acids such as glutamine, asparagine, and tryptophan. Discovering a Ramachandran φ-dihedral angle spectroscopic marker would be especially powerful for constraining the structure of the peptide backbone in fibrils. Work by Schweitzer-Stenner and coworkers describes an interesting approach to analyze the Amide I band to determine both Ramachandran ψ-and φangles. However, it remains unclear whether their methodology can be applied to systems beyond tetrapeptides.