Vibrational Raman and Raman Optical Activity Spectra of d -Lactic Acid, d -Lactate, and d -Glyceraldehyde: Ab Initio Calculations

Vibrational Raman and Raman optical activity (VROA) spectra have been obtained ab initio for various conformations of d -lactic acid, d -lactate, and d -glyceraldehyde. The calculations have been carried out at the linear response self-consistent field level. The VROA spectra have been found to be very sensitive to the conformational changes. The VROA parameter of the stretching vibration of the carbonyl group is shown to be a promising parameter for structural investigations because it changes sign when a short internal hydrogen bond OH···OC is formed. Raman spectra do not exhibit such sensitivity to the molecular conformation, although an analysis of the stretching vibrations of the hydroxyl group can also be helpful in localizing internal hydrogen bonds.