Ammonium DiNitramide (ADN) is one of the most promising green energeticoxidizers for future rocket propellant formulations. In the present work, wereport a detailed theoretical study on structural, elastic, and vibrationalproperties of the emerging oxidizer under hydrostatic compression using variousdispersion correction methods to capture weak intermolecular (van der Waals andhydrogen bonding) interactions. The calculated ground state lattice parameters,axial compressibilities, and equation of state are in good accord with theavailable experimental results. Strength of intermolecular interactions hasbeen correlated using the calculated compressibility curves and elastic moduli.Apart from this, we also observe discontinuities in the structural parametersand elastic constants as a function of pressure. Pictorial representation andquantification of intermolecular interactions are described by the 3D Hirshfeldsurfaces and 2D finger print maps. In addition, the computed infra-red (IR)spectra at ambient pressure reveal that ADN is found to have more hygroscopicnature over Ammonium Perchlorate (AP) due to the presence of strong hydrogenbonding. Pressure dependent IR spectra show blue- and red-shift of bending andstretching frequencies which leads to weakening and strengthening of thehydrogen bonding below and above 5 GPa, respectively. The abrupt changes in thecalculated structural, mechanical, and IR spectra suggest that ADN mightundergo a first order structural transformation to a high pressure phase around5-6 GPa. From the predicted detonation properties, ADN is found to have highand low performance characteristics when compared with ammonium based energeticoxidizers and well-known secondary explosives, respectively.
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