We next assess whether the ddG signal originates from MCSs of the DIPA and water. We study the evolution of the ddGs as a function of temperature and composition and show that they evolve as we would expect according to the known DIPA-water phase diagram (Error! Reference source not found.A). of the Supplemental Information. (E) ddG of mixtures ranging from xA = 0.1 to 0.8. A significant composition dependence was observable in the broad peaks at 3.7 Å and 7.5 Å and the abutting troughs. (F) The same ddG normalized by the mole fraction of water, xW = 1 -xA, and scaled by an arbitrary factor b for visual clarity. This normalization eliminated the composition dependence of the signal, suggesting that the amplitude of the ddG signal is a linear function of the mixture composition.