A Comprehensive Chemical Dynamics Study on the Decomposition Mechanism of Nitramine-/Nitro-Amine-Based Energetic Materials and Their Cocrystal in the Condensed Phase
Abstract
This project aims to explore experimentally and computationally the fundamental mechanisms of the decomposition of key representatives of nitramine-based energetic materials (HMX), nitro-amine-based energetic materials (FOX-7), and their cocrystal in the condensed-phase (solid state). To date, no comprehensive study has been conducted in the condensed-phase, in which the decomposition mechanisms of these materials, the overall spectrum of their products, and the nature of the decrease in sensibility of the cocrystal, have been explored. This research will push the boundary of our knowledge on the interplay between the structure of the energetical material and its performance, while shed light on the design and synthesis of the next-generation energetical material. The decomposition of these condensed-phase energetic materials will be initiated by infrared multiphoton dissociation (IRMPD) and single photon ultraviolet photodissociation (UVPD). In an ultra-high vacuum machine, the decomposition will be monitored on line and in situ within the solid state via Fourier Transform Infrared (FTIR), Raman, and ultraviolet-visible (UV-VIS) spectroscopy; gas phase product will be probed via isomer selective single vacuum ultraviolet (VUV) photon soft ionization followed by a mass spectroscopic analysis in a reflectron time-of-flight mass spectrometer (ReTOF-MS). A finite cluster, including the photon-excited molecule and its immediate neighbor, will be employed to mimic the condensed-phase environment in the computation. Benchmarked by higher level ab initio theory performed in the gas phase, the potential energy surfaces of the reactions will be characterized with density functional theory (DFT) and time-dependent DFT, for the ground and excited state, respectively. The non-adiabatic decomposition in the gas and condensed-phase will be simulated with semiempirical floating occupation molecular orbital configuration interaction (FOMO-CI). The parameters of the semiempirical method will be recalibrated to accurately represent the system.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 21, 2022
- Source ID
- FA95502110221XX0
Entities
People
- Rui Sun
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Hawaiʻi System