Quantum-Chemical Comprehensive Study of the Organophosphorus Compounds Adsorption on Zinc Oxide Surfaces

Abstract

Ab initio calculations at the density functional theory and the second-order Moller−Plesset perturbation theory levels, and using the n-layered integrated molecular orbital and molecular mechanics (ONIOM) method, have been performed for the adsorption of dimethyl methylphosphonate (DMMP) and tabun (GA) on (ZnO)n (where n = 4, 18, or 24 molecular clusters of (1010) and (0001) zinc oxide surfaces). Different adsorption sites and DMMP orientations were considered. Calculations include the evaluation of the optimized geometries, atomic charges, interaction energies, various methods applied, and different sizes and surface types of the ZnO fragments. On both surfaces, the molecular adsorption proceeds as chemisorption via the formation of a Zn···O chemical bond in the case of the DMMP adsorption complex and a P···O covalent bond or a Zn···N chemical bond for GA adsorption complexes. The type of surface greatly affected the strength of the intermolecular interactions and the interaction energies. The results in...