AIMS simulation study of ultrafast electronically nonadiabatic chemistry of methyl azide and UV-VIS spectroscopic study of azido-based energetic plasticizer bis(1,3-diazido prop-2-yl)malonate

To gain insight into the ultrafast electronically nonadiabatic chemistry of azido-based energetic plasticizer, we have explored the nonadiabatic chemical dynamics of an azido-based model analog molecule, methyl azide (MAz), using ab initio multiple spawning (AIMS) simulation and electronic structure theory calculations. Molecular nitrogen (N-2) is predicted to be the initial product of MAz following its electronic excitation to the S-1 electronically excited state. AIMS-based simulation reveals that electronically excited azido-based molecules undergo extremely fast (approximately in 40 femtoseconds) relaxation to the ground state via the (S-1/S-0) CI conical intersection. Furthermore, this relaxation process involves the N-N bond elongation along with the bending of N-3 moiety. This is the first report on the electronically non-adiabatic chemical dynamics (in ultrafast time domain) of methyl azide. Finally, using ultraviolet-visible (UV-VIS) spectroscopy, we comment on the electronically nonadiabatic chemistry of azido-based energetic plasticizer, bis(1,3-diazido prop-2-yl) malonate. (C) 2017 Elsevier B.V. All rights reserved