Ab Initio Treatment of the RDX-siloxane Site Surface of Clay Minerals

The identification of landmines in soil is actually a particular problem around the world. One of the high explosives studied in the past few years is hexahydro-1,3,5-trinitro-s-triazine as well know as RDX. In this work, interactions of RDX with the basal siloxane surface of the clay mineral kaolinite has been perform using computational modeling (Gaussian 03), in order to determine the spectroscopic signature of RDX adsorbed onto clay minerals. In the first part of this work, we performed the optimization geometry and vibrational analysis of three lower-energy conformers. The three lower-energy conformers are distinguished by the arrangement of the nitro groups relative to the triazine ring of the RDX molecule. Two of these conformers have C3V symmetry which corresponds to beta form, while the third conformer has Cs symmetry and corresponds to the alpha form. The best results, in the optimization of the three conformers were perform using density functional methods (DFT) at the B3LYP/6-311+G (d,p) level of theory. (Abstract shortened by UMI.)