Links between surface electrostatic potentials of energetic molecules, impact sensitivities and C–NO₂/N–NO₂ bond dissociation energies

Abstract

Earlier work has shown a link—not necessarily a causal relationship—between the impact sensitivities of energetic compounds and the electrostatic potentials on their molecular surfaces. The latter are anomalous in that the positive regions are strikingly dominant, contrary to what is typical of organic molecules. In this work, we show that the presence of several electron-withdrawing NO₂ groups and/or aza nitrogens (common features of energetic systems), which is the reason for the anomalously positive surface potentials, also weakens the C–NO₂ and/or N–NO₂ bonds. Thus, insofar as these are trigger linkages, the rupture of which is a key step in detonation initiation, an approximate correlation between the features of the surface potentials and sensitivity may be expected. A group of eight nitramines is used to demonstrate this. Work is in progress to elucidate the basis for the surface potential–sensitivity link when a non-trigger-linkage mechanism is operative.

Keywords:

• electrostatic potentials
• impact sensitivity
• energetic compounds
• dissociation energies

Acknowledgement

We greatly appreciate the support of this work by the Defense Threat Reduction Agency, DTRA grant No. HDTRA1-07-1-0002, Project Officer Dr. William H. Wilson.