(675e) Contaminant Adsorption on ?-Alumina Surface As Predicted By the Plane-Wave Density Functional Theory

Alumina is one of the most important ceramic materials and possesses highly insulation property. It is characterized by the combination of both ionic and covalent bonding. The α-phase of the alumina (α-Al₂O₃) which is also called corundum is the most stable phase. The Al-terminated layer of the (0001) surface of α-Al₂O₃ has been suggested to be more stable than the oxygen-terminated surface. Water binding on the metal-oxide surfaces is a complex phenomenon. Such binding is affected by several factors such as surface structure, and acidity and basicity of surface metal and oxygen sites respectively. The Al-terminated α-alumina surface is hydroxylated in the presence of water. Adsorption of high energy military contaminants on different surfaces is an important area of research since such studies can provide significant information on fate and effects of these contaminants in the environments. In the present work, we discuss the adsorption of some explosive compounds on the alumina surface at the plane-wave Density Functional Theory level using the PBE and van der Waals functionals. Vanderbilt ultrasoft pseudopotentials were used to model interaction of electron with core. Both parallel and perpendicular orientations of adsorbates with respect to alumina surface were considered. The electronic structures and the nature of interaction of adsorbates on alumina surface with and without the presence of water molecules will be discussed.