Polarized Laser Raman Studies of Biological Polymers

A group‐theoretical analysis of the Raman tensor for helical polymers is given and illustrated for the Pauling $\alpha$ helix which possesses 18 residues in five turns. A detailed determination of the polarized Raman spectra is given for oriented α‐helical poly‐l‐alanine fibers and for four polyribonucleotides in solution. Tentative assignments to ${\mathrm{A,\; E}}_1$ , and $E_2$ symmetry are made on certain Raman bands of poly‐l‐alanine based on the polarization of the Raman light. A detailed comparison of monomer and polymer bands are given for the four polynucleotides. A theory for the angular dependence of Raman light scattered from helical molecules is given.