Role of electronic excitations in explosive decomposition of solids

A combined theoretical and experimental study is performed for the initiati on of chemistry process in high explosive crystals from a solid-state physi cs viewpoint. In particular, we were looking for the relationship between t he defect-induced deformation of the electronic structure of solids, electr onic excitations, and chemical reactions under shock conditions. Band struc ture calculations by means of the Hartree-Fock method with correlation corr ections were done to model an effect of a strong compression induced by a s hock/impact wave on the crystals with and without edge dislocations. Based on the obtained results, an excitonic mechanism of the earliest stages for initiation of high explosive solids is suggested with application to cyclot rimethylene trinitramine (also known as RDX) crystal. Experimental tests of this mechanism for AgN3 decomposition controlled by the dislocation densit y were worked out. The use of pulse radiolysis techniques allows us to obse rve pre-explosion modifications in properties and behavior of the solids. P re-explosion conductivity and pre-explosion luminescence measurements for a series of heavy metal azides lead us to the model for the development of t he decomposition chain reaction. Thus, the key role of electronic excitatio ns facilitated by edge dislocations in explosive solids is established and analyzed. Practical applications of the suggested mechanisms are discussed. (C) 2001 American Institute of Physics.