Role of inter- and intramolecular bonding on impact sensitivity.

ABSTRACT

A picture of impact sensitivity based on the bond bundles of the electron charge density is developed, allowing the role of both inter- and intramolecular bonding interactions to be investigated. Impact sensitive materials were found to have a convergent intramolecular bond bundle with a low electron count that serves as a trigger linkage, while insensitive materials do not. The shape and electron count of the intramolecular bond bundles was found to change between the gas phase and solid state due to the formation of intermolecular bond bundles. In the case of polynitrobenzenes, this change was subtle and did not affect the trigger linkages. However, the intermolecular bond bundles in crystalline RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) change from C-N trigger linkages in the gas phase to N-N trigger linkages in the solid state. This observation offers a theoretical justification of the experimentally observed differences in the decomposition behavior of gas phase and crystalline RDX.