Neutron Spectroscopy, IR, Raman and Ab Initio Study of L-Proline

Inelastic incoherent neutron scattering spectra (IINS) were obtained for normal and deuterated L-proline. Raman and infrared spectra were also recorded. Geometries were optimized for the zwitterion form using ab initio Hartree-Fock (HF) level with 6-31G*, 6-311G** and 6-311++G** basis sets. Force fields and normal modes were calculated and used as basis for an assignment of the spectral features. The theoretical frequencies of normal and d2 - L-proline were compared with IINS spectra.