Speaker: David S. Moore
Shock & Detonation Physics Group
Laser Spectroscopy of Energetic Materials
Energetic materials are used as propellants, explosives, pyrotechnics, and fuels. Explosives are energetic materials that quickly release their stored energy (usually chemical) after some kind of insult, such as impact, heat, friction, or electrostatic discharge. The fast release of energy usually propagates through the material as a reactive wave. A detonation occurs when the reactive wave moves supersonically through the energetic material. The detonation shock wave drives the energetic material to enormous pressures (hundreds of thousands of atmospheres) in an extremely short time (nanoseconds or less), which causes the chemical reactions that eventually produce stable products and the enormous release of stored chemical energy. The actual chemical reactions that occur at the onset of this process have been theorized but not yet observed in real time under detonation conditions.
Laser spectroscopy is being used to observe these chemical reactions as they occur, and the chemical mechanism is being unraveled with guidance from quantum molecular dynamics simulations. Laser spectroscopy is also being used to detect the presence of energetic materials in scenarios of interest to aviation and national security. I will discuss both of these applications of laser spectroscopy in this colloquium.