Neutron spectroscopic study of hydrogen bonding dynamics in L-serine

Inelastic incoherent neutron scattering (IINS) spectra were obtained at 10 K for normal and deuterated L-serine. The geometry of L-serine molecule was optimized for the zwitterion form using ab initio HF, MP2 and DFT (B3LYP) levels with 6-31G* and 6-311 + +G4** basis sets. The theoretical frequencies of normal and d4-L-serine were compared with IINS spectra. Normal coordinate analysis and band assignments based on ab initio calculations and experimental data were presented. IINS frequencies due to the out-of-plane gamma(N-H...O) hydrogen bond motions were observed and identified.