Figure shows the N-O and O-O partial PDFs computed from MD, GNO and GOO. Both exhibit a first sharp peak at r = 2.8 Å, representing N-H-O and O-H-O hydrogen bonding, respectively. These peaks are at almost the same position and have almost the same shape and width as each other. This further signifies that if a water molecule goes into solution in a DIPA-rich phase and replaces an O-H-O hydrogen bond with an O-H-N hydrogen bond, we expect virtually no change in the measured PDF at the position of this peak. This further means that the difference process used to obtain the ddG will likely cancel peaks in ddG at that location. In other words, the overlap in GNO and GNN at low r explains the lack of a strong hydrogen-bond peak in the ddG (Figure ).