title: Explanation of the colossal detonation sensitivity of silicon pentaerythritol tetranitrate (Si-PETN) explosive.
abstract: DFT calculations have identified the novel rearrangement shown here for decomposition of the Si derivative of the PETN explosive [PentaErythritol TetraNitrate (PETN), C(CH(2)ONO(2))(4)] that explains the very dramatic increase in sensitivity observed experimentally. The critical difference is that Si-PETN allows a favorable five-coordinate transition state in which the new Si-O and C-O bonds form simultaneously, leading to a transition state barrier of 33 kcal/mol (it is 80 kcal/mol for PETN) and much lower than the normal O-NO(2) bond fission observed in other energetic materials (approximately 40 kcal/mol). In addition this new mechanism is very exothermic (45 kcal/mol) leading to a large net energy release at the very early stages of Si-PETN decomposition that facilitates a rapid temperature increase and expansion of the reaction zone.
authors.affiliation: Materials and Process Simulation Center, 139-74, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Wei-Guang
authors.initials: WG
authors.lastname: Liu
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Zybin
authors.forename: Siddharth
authors.initials: S
authors.lastname: Dasgupta
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Klapötke
authors.forename: William A
authors.initials: WA
authors.lastname: Goddard