The N-N partial PDF, GNN, computed between nitrogen atoms in the MD ensemble, is also shown in Figure . GNN has no peak at r = 2.8 Å, the position of the hydrogen bond, indicating that there are virtually no direct N-H-N hydrogen bonds in the mixture. Despite this, there are well-defined, broad peaks and valleys in the regions around 7 Å and 12.5 Å that line up quite well with the broad peaks in the ddG. This can be explained if the MCSs formed are similar to the DIPA-water-DIPA dumbbells discussed from the small-box modeling above, where nitrogen atoms are held in place relative to each other by well-defined water hydrogen bonding intermediaries.