The Responses of Energetic Materials under Indirect Ultrafast Heating: Polarization Dependence of Heat Transfer in Materials
Abstract
The primary motivation for this work is the desire to understand the behavior and role of temperature induced by picosecond heat pulses generated from interactions of femtosecond laser pulses on gold (Au) films. Using the indirect ultrafast laser heating technique coupled with transient visible absorption spectroscopy, we investigate how thermal energy generated from the heat pulses interacts with energetic materials. Previously, using this technique we have successfully shown that the thermal energy couples into explosive molecules by changing electronic configurations of the molecules in the excited state, and the changes are temperature dependent. In addition, we found that thermal energy coupling to the energetic molecules was dependent on physical properties of the samples such as thermal conductivity and electron-phonon coupling. In this work, we further show that the method of polarization-resolved transient absorption spectroscopy coupled with the ultrafast indirect heating technique can detect the orientations of liquid dipolar nitromethane molecules that are oriented and aligned due to the thermal gradient generated by heat flow from Au into the liquid sample in the picosecond time scale. Also reported here is the investigation of the dependence of thermal energy coupling into molecules on the orientation of 1, 3, 5-trinitroperhydro-1, 3, 5-triazine (RDX) using the ultrafast indirect heating technique coupled with polarization-resolved transient absorption spectroscopy. The results of this investigation show that the coupling of thermal energy into RDX molecules was dependent on the orientations of the sample.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2023
- Accession Number
- AD1207920
Entities
People
- Frank C. Jr De Lucia
- Jennifer L Gottfried
- Nhan C. Dang
Organizations
- United States Army Research Laboratory