The CHI (Carbohydrate Intrinsic) energy functions score oligosaccharide structures based on glycosidic linkage conformations. Glycosidic torsion angles that deviate from the calculated global energy minima are penalized according to the energy curves. The functions were developed by fitting Gaussian equations to the torsional energy profiles of tetrahydropyran-based disaccharide models, which were obtained using quantum mechanical calculations.
Currently, the CHI energy functions can be applied to all standard two-bond glycosidic linkages between pyranoses in the chair conformation.
A. K. Nivedha, S. Makeneni, B. L. Foley, M. B. Tessier , R. J. Woods, J. Comput. Chem. 2014, 35, 526–539. DOI: 10.1002/jcc.23517