Shock response of condensed-phase RDX: molecular dynamics simulations in conjunction with the MSST method

Abstract

We have performed molecular dynamics simulations in conjunction with the multiscale shock technique (MSST) to study the initial chemical processes of condensed-phase RDX under various shock velocities (8 km s⁻¹, 10 km s⁻¹ and 11 km s⁻¹). A self-consistent charge density functional tight-binding (SCC-DFTB) method was used. We find that the N–NO₂ bond dissociation is the primary pathway for RDX with the NO₂ groups facing (group 1) the shock, whereas the C–N bond scission is the dominant primary channel for RDX with the NO₂ groups facing away from (group 2) the shock. In addition, our results present that the NO₂ groups facing away from the shock are rather inert to shock loading. Moreover, the reaction pathways of a single RDX molecule under the 11 km s⁻¹ shock velocity have been mapped out in detail, NO₂, NO, N₂O, CO and N₂ were the main products.