FT-IR microspectroscopy of RDX interactions with clay minerals.

摘要

Detection of trace level explosives is a challenging field of great importance to national security and landmine detection. Chemical signatures of buried landmines are in a very complex environment. External physical conditions that affect explosive vapors and particles in soil can affect the explosive chemical signature. The chemical spectroscopic signature of the RDX in clay soil environments has been investigated by means of reflectance FT-IR microspectroscopy. Soil obtained from the University of Puerto Rico at Mayaguez was treated using the textural mechanical method in order to separate the clay from all the other components in the soil. B3LYP/6-311G** calculations performed on the conformers of RDX helped determine its most stable conformations, their symmetry, and vibrational spectra. The IR microspectroscopic study showed that the RDX-Clay mineral complex and its interactions can be detected using the FT-IR technique. Variations in the clay's pH revealed changes in the RDX-Clay complex spectroscopic signature. It is suggested that the electron donor nitrogen atoms from RDX are interacting with the electron acceptor oxygen atoms of the edge sites of the clay's surface.