Raman Optical Activity of Glucose and Sorbose in Extended Wavenumber Range.

Raman optical activity (ROA) is pursued as a promising method for structural analyses of sugars in aqueous solutions. In the present study, experimental Raman and ROA spectra of glucose and sorbose obtained in an extended range (50 - 4000 cm -1 ) are interpreted using molecular dynamics and density functional theory, with the emphasis on CH stretching modes. A reasonable theoretical basis for spectral interpretation was obtained already at the harmonic level. Anharmonic corrections led to minor shifts of band positions (up to 25 cm -1 ) below 2000 cm -1 , while the CH stretching bands shifted more, by ~180 cm -1 . However, the anharmonicities could be included on a relatively low approximation level only, and did not always improve the harmonic band shapes. The dependence on the structure and conformation shows that the CH stretching ROA spectral pattern is a sensitive marker useful in saccharide structure studies.