The identified CH-p stacking interactions involve multiple glycan C-H bonds positioned over the aromatic ring. Thus, we used functional group SAPT (i.e., F-SAPT) to decompose the interaction energies into the energetic contributions from different regions of galactose. This analysis provides a measure of interaction strength between distinct functional groups (i.e., portions of a molecule). For galactose residues, we defined each "functional group" as containing one galactose heavy atom (either carbon or oxygen) and any bonded hydrogen atom(s) (Figure ).