Investigation of the Role of Electronic Excitations in Shock-Induced Initiations of Explosives Using an Optical Pump-Probe Technique

Author(s):

Frank C. De Lucia and Nhan C. Dang

Abstract:

Electronic excitation has been identified as playing a key role in the explosive initiation process in both experimental and theoretical research. Therefore, to develop a complete mechanism for explosive initiation, understanding the early timescale electronic excitations during a shock-induced initiation is essential for predictive capability. However, energies that drive electronic excitations in the initiation are a convolution of rapidly changing temperature, pressure and strain, etc., generated during the shock loading. It is difficult to extract an accurate mechanism for electronic excitations in the initiation events without a standard mechanism. To build a standard mechanism, electronic excitations of high-energetic materials under an optical pump have been performed at the US Army Combat Capabilities Development Command Army Research Laboratory. Here, we report results from the optical pump-probe experiment developed for these studies. With this setup, we can obtain more reliable data compared to earlier works. Therefore, our results can provide experimental parameters to accurately determine a standard electronic excitation mechanism for Army materials of interest. We further propose and discuss future studies of determining the role(s) of electronic excitations in potentially enhancing the performance of an explosive.