Monosaccharide-water complexes: vibrational spectroscopy and anharmonic potentials.

Area of Science:

• Computational Chemistry
• Spectroscopy
• Carbohydrate Chemistry

Background:

• Monosaccharide complexes play crucial roles in biological systems.
• Accurate vibrational spectra are essential for structural elucidation and understanding intermolecular interactions.
• Previous computational methods have limitations in reproducing experimental vibrational data.

Purpose of the Study:

• To predict and analyze the vibrational spectra of various monosaccharide·D(2)O complexes using advanced computational methods.
• To assess the accuracy of ab initio vibrational self-consistent field (VSCF) calculations, including anharmonic corrections (VSCF-PT2), against experimental data.
• To provide a robust computational framework for the assignment of vibrational spectra and the study of carbohydrate interactions.

Main Methods:

• Ab initio vibrational self-consistent field (VSCF) calculations were performed.
• Anharmonic VSCF-PT2 frequencies were computed using hybrid HF/MP2 potentials.
• Calculated spectra were compared with experimental data for phenyl-tagged monosaccharide·D(2)O complexes.

Main Results:

• High accuracy was achieved, with average discrepancies between calculated and experimental frequencies around 1.0-1.5%.
• The VSCF-PT2 method effectively reproduced vibrational anharmonicities.
• The study validated the use of first-principles spectroscopic calculations without empirical scaling.

Conclusions:

• Ab initio VSCF calculations provide highly accurate vibrational spectra for monosaccharide·D(2)O complexes.
• These computational methods are reliable for assigning vibrational spectra of carbohydrates.
• The study enhances the understanding of intra- and intermolecular interactions in carbohydrate systems.