Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 66: Oxide Surfaces II

O 66.4: Vortrag

Donnerstag, 14. März 2013, 11:15–11:30, H42

Ab initio calculations on the adsorption energy of NO on TiO₂(110) — •Marie Arndt and Thorsten Klüner — Theoretische Chemie, Carl von Ossietzky Universität Oldenburg, Germany

Photocatalytic reactions on metaloxide surfaces are an important section in technical industries. An outstanding photocatalyst is the semiconductor titaniumdioxide. In this context, the adsorption and desorption processes of small molecules on the substrate surfaces play an important role in theoretical and experimental analysis. This study focuses on the characterization of the adsorption of NO on a rutile(110) surface. We investigated the adsorption by using ab initio calculations, such as restricted open shell Hartree-Fock and restricted open shell Møller-Plesset second order perturbation theory. To describe the electronic ground state of this open shell system, an embedded cluster model of the type Ti₉O₁₈Mg₇¹⁴⁺ was used. Using the Molcas[1] quantum chemistry package, the goal is to find the global minimum of the adsorption energy. Within our model, six degrees of freedom of our diatomic NO molecule on a rigid TiO₂ surface are defined. In this study, we varied the desorption coordinate z and the polar angle θ, by keeping the lateral coordinates x and y, the azimuthal angle ϕ and the NO bond length r fixed. The preferred orientation of NO on the rutile(110) surface has been found by modeling a 2D potential energy surface and is discussed in terms of a molecular orbital picture. The results revealed a tilted orientation of the NO at a distance of 3.0 Å to the surface. [1] Division of Theoretical Chemistry, Molcas 7.6, Lund University, 2011.