Prediction of Vibrational Spectra of Polysaccharides—Simulated IR Spectrum of Cellulose Based on Density Functional Theory (DFT)

The continuing developments of electronic structure methods may provide insight into the vibrational spectroscopy of polysaccharides, which was not accessible to older works on this subject. The present work shows for the first time how main features of cellulose infrared spectra can be predicted and assigned using simple single chain models of cellulose combined with density functional theory prediction of their vibrational properties. The results provide a more informed basis for assigning cellulose IR bands and may resolve some of the challenges associated with the molecular origin of "marker" bands, which are commonly used to measure properties such as crystallinity or crystalline forms. The theoretical approach can be seen as a first-order approximation, which can be further improved.