TY - JOUR A1 - Michalchuk, Adam A1 - Hemingway, J. A1 - Morrison, C. T1 - Predicting the Impact Sensitivities of Energetic Materials through Zone-Center Phonon Up-Pumping N2 - The development of new energetic materials (EMs) is accompanied by significant hazards, prompting interest in their computational design. Before reliable in silico design strategies can be realized, however, approaches to understand and predict EM response to mechanical impact must be developed. We present here a fully ab initio model based in phonon up-pumping which successfully ranks the relative impact sensitivity of a series of organic EMs. The methodology depends only on the crystallographic unit cell and Brillouin zone center vibrational frequencies. We therefore expect this approach to become an integral tool in the large-scale screening of potential EMs. KW - Energetic materials KW - Ab initio simulation PY - 2021 U6 - https://doi.org/10.1063/5.0036927 VL - 154 IS - 6 SP - 064105 AN - OPUS4-52146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Michalchuk, Adam T1 - The Mechanochemical Excitation of Crystalline LiN3 N2 - Mechanochemical reactions are driven by the direct absorption of mechanical energy by a solid (often crystalline) material. Understanding how this energy is absorbed and ultimately causes a chemical transformation is essential for understanding the elementary stages of mechanochemical transformations. Using as a model system the energetic material LiN3 we here consider how vibrational energy flows through the crystal structure. By considering the compression response of the crystalline material we identify the partitioning of energy into an initial vibrational excitation. Subsequent energy flow is based on concepts of phonon–phonon scattering, which we calculate within a quasi-equilibrium model facilitated by phonon scattering data obtained from Density Functional Theory (DFT). Using this model we demonstrate how the moments (picoseconds) immediately following mechanical impact lead to significant thermal excitation of crystalline LiN3, sufficient to drive marked changes in its electronic structure and hence chemical reactivity. This work paves the way towards an ab initio approach to studying elementary processes in mechanochemical reactions involving crystalline solids. KW - Energetic materials KW - Ab initio simulation KW - DFT KW - Mechanochemistry PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-559310 SP - 1 EP - 20 PB - Royal Society of Chemistry AN - OPUS4-55931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -