The aim of this proposal is to explore the effects of high pressure on the crystal structure of the widely used explosive, nitroglycerin (NG), with a particular focus on changes in intermolecular interactions and on possible phase transitions. For the first time, a high-quality, experimental equation of state for NG will be obtained. The high-quality structural data that will be acquired, including the effects of pressure on hydrogen-bonding motifs and voids within the crystal structure, will provide insight into molecular energy transfer, detonation mechanisms and, in this case, the sensitivity to initiation. The results will be of particular value in developing further our model for predicting sensitivities of energetic materials based on energy transfer (up-pumping) between low-energy phonon modes and more localised vibrational modes associated with specific bond-breaking processes