Date Published:
NOV 22Abstract:
Ab initio vibrational self-consistent field (VSCF) calculations are used to predict-the vibrational spectra of an extended series of monosaccharide center dot D2O complexes, including glucose; galactose, mannose, xylose, and fucose in their alpha and beta anomeric; forms, and Compared with recently published experimental data for T their (phenyl-tagged) complexes. Anharmonic VSCF-PT2 frequencies are calculated directly, using ab initio hybrid HF/MP2 potentials, to assess their accuracy in reproducing the vibrational anharmonicities and provide a more rigorous basis for vibrational and structural assignments. The average discrepancies between the calculated and experimental frequencies are similar to 1.0-1.5%, and the first-principles spectroscopic calculations, free of any empirical scaling, yield results: of high accuracy. They encourage confidence in their future application. to the assignment of other carbohydrate systems, both free and complexed, and an improved understanding of their intra- and intermolecular carbohydrate interactions.
