Thermal decomposition of condensed-phase nitromethane from molecular dynamics from reaxff reactive dynamics

Si Ping Han, Adri C.T. Van Duin, William A. Goddard, Alejandro Strachan

Research output: Contribution to journalArticlepeer-review

93 Scopus citations

Abstract

We studied the thermal decomposition and subsequent reaction of the energetic material nitromethane (CH3NO2) using molecular dynamics with ReaxFF, a first principles-based reactive force field. We characterize the chemistry of liquid and solid nitromethane at high temperatures (2000-3000 K) and density 1.97 g/cm3 for times up to 200 ps. At T = 3000 K the first reaction in the decomposition of nitromethane is an intermolecular proton transfer leading to CH3NOOH and CH2NO2. For lower temperatures (T = 2500 and 2000 K) the first reaction during decomposition is often an isomerization reaction involving the scission of the C-N bond the formation of a C-O bond to form methyl nitrate (CH3ONO). Also at very early times we observe intramolecular proton transfer events. The main product of these reactions isH2Owhich starts forming following those initiation steps. The appearance ofH2Omarks the beginning of the exothermic chemistry. Recent quantum-mechanics-based molecular dynamics simulations on the chemical reactions and time scales for decomposition of a crystalline sample heated to T = 3000 K for a few picoseconds are in excellent agreement with our results, providing an important, direct validation of ReaxFF.

Original languageEnglish (US)
Pages (from-to)6534-6540
Number of pages7
JournalJournal of Physical Chemistry B
Volume115
Issue number20
DOIs
StatePublished - May 26 2011

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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