Raman scattering tensors of adenine.

Polarized Raman scattering measurements have been made of a single crystal of adenine dihydrochloride (adenine-2H+) by the use of Raman microscope with 488.0 nm excitation. The adenine-2H+ crystal belongs to the space group Pnma (orthorhombic), and Raman intensities of Iaa, Ibb, Icc and Iac (which correspond to the aa, bb, cc and ac components of the crystal Raman tensor) have been determined for each Raman band. The depolarization ratios of Raman bands have been observed for fully random molecular orientations in an adenine 6N HCl aqueous solution. From these experimental data, and by taking the known crystal structure into account, anisotropic and isotropic molecular Raman scattering tensors have been determined for each vibrational mode of the adenine residue.