Interfacial Chemical Kinetics and Mechanisms Involving Chemical Simulants under Dynamic Thermal Conditions
Abstract
A comprehensive research program will be carried out under the auspices of DTRA that will extend significantly our fundamental understanding of the surface chemistry of adsorbed simulants under rapidly changing thermal conditions and elevated temperatures. Studies that involve chemical simulants, that is, molecules that serve as realistic but safe mimics for the agents that are the actual chemical warfare species, provide crucial insights into the fundamental processes that can be used for the desired efficacious destruction of chemical agents. This new effort will focus on the effectiveness of various heating and blast scenarios needed to achieve chemical warfare agent destruction and mitigation, and assessment of residual persistence and dispersal after thermal exposure. Three of the most sensitive approaches to studying surface chemistry, molecular beam scattering, scanning probe imaging microscopy, and precision interfacial characterization spectroscopies including in situ x-ray spectroscopy, Auger spectroscopy for elemental analysis, and infrared spectroscopy for molecular identification of adsorbed species will elucidate fundamental molecular-level insights into interfacial processes relevant to national defense. On-surface thermal conditions will span 500-2000 degrees with ramping rates encompassing 100-10,000 degrees/sec using laser and other rapid heating methods. A unique three-supersonic beam gas-surface interactions instrument will elucidate simulant adsorption, on-surface chemistry, and characterize the desorbing reaction products and remaining parent species. Energy release upon such rapid heating conditions will also be quantified, including the influence of gas-phase collisions in the desorption plume, using highly sensitive mass spectrometry. These measurements can be done in the presence of atmospheric gases, including oxygen, nitrogen, CO and water, and added halogens and sulfides. Measurements under atmospheric pressure will be done to validate insights gained from vacuum-based surface chemistry measurements. Another unique aspect will be the ability to quantify simulant fate and dispersal arising from energetic simulant-surface collision energies from thermal-2000 degrees, giving insight into the mechanistic chemistry that occurs during thermal blast conditions. In order to validate the connection between our university simulant studies and agent chemistry, related agent work will be done by research partners at the Edgewood Chemical Biological Center. Surfaces to be studied will include mimics and samples of concrete, steel, soil, metals, metal oxides, reactive surfaces, and other environmental materials. This program will educate the next generation of leaders in the destruction of chemical warfare agents, providing personnel development and training in areas that are of critical importance to the DoD.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 26, 2016
- Source ID
- HDTRA11610024
Entities
People
- Steven J. Sibener
Organizations
- Defense Threat Reduction Agency
- University of Chicago