Adsorption and decomposition of organophosphonates on MoO2: A DFT and APXPS study*

Our knowledge of interactions of toxic chemical warfare agents (CWAs) with existing filter materials is scarce, as experiments with these toxic agents required special facilities and hence they are beyond capabilities of most research groups. DFT modeling provides an opportunity to explore various physical and chemical properties of CWAs including their reactivity in the gas phase, liquid solutions and interfaces with filter materials. While outcome of the modeling depends on many factors, results of experimental measurements can serve as reference data and validation for theoretical studies. We report results of our joint APXPS and DFT study of interactions of organophosphonate compounds with a MoO₂ surface. Solid state periodic calculations were initially used to aid with an interpretation of APXPS measurements to explore adsorption and decomposition of DMMP on MoO₂ surface. Once the good qualitative agreement between theory and experiment was established, DFT modeling was employed to investigate mechanisms of decomposition of highly toxic sarin on MoO2 (011) surface.