TY - JOUR A1 - Michalchuk, Adam A1 - Morrison, C. T1 - From lattice vibrations to molecular dissociation JF - Theoretical and Computational Chemistry N2 - The ease with which an energetic material can be initiated by mechanical impact is a critical parameter directing material safety and application. While impact sensitivity metrics are traditionally derived experimentally, recent developments have highlighted that the phenomenon is amenable to first principles simulation. In this chapter, we will outline a fully ab initio approach to predict the relative impact sensitivities of energetic materials based on the mechanochemical principles that link the impact event to vibrational energy transfer. This mechanism is key to rationalizing how a mechanical impact—which deposits energy into the low-frequency lattice vibrations—results in a molecular response. By simulating the vibrational energy levels (the so-called phonon density of states, PDOS) using first-principles computational methods (typically dispersion-corrected plane-wave density functional theory, PW-DFT) we can calculate the relative rate of energy propagation from the delocalized low-energy lattice vibrations through to the localized molecular modes. The latter traps the energy, which eventually results in bond rupture through heightened vibrational excitation. This method, based on vibrational up-pumping, offers a route toward predicting the impact sensitivities of a broad range of energetic materials, provided the crystal structure of the compound (or salt or co-crystal) is known. While it does not offer insight into the sensitizing roles undoubtedly played by crystal defects or grain boundaries, it does provide a level of understanding at the molecular and crystal packing levels. Correspondingly, this approach offers a feedback mechanism to chemists and materials scientists to guide the design of new materials with desired impact sensitivity behavior. KW - Energetic materials KW - Density functional theory KW - Material design PY - 2022 DO - https://doi.org/10.1016/B978-0-12-822971-2.00010-3 VL - 22 SP - 215 EP - 232 PB - Elsevier B.V. AN - OPUS4-54717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -