Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 60: Dielectric and Molecular/Water Interfaces
O 60.2: Talk
Wednesday, March 18, 2015, 15:15–15:30, MA 043
Quantum chemical and quantum dynamical studies of the photocatalytic water splitting on titanium dioxide — •Jan Mitschker and Thorsten Klüner — Theoretische Chemie, Carl von Ossietzky Universität Oldenburg
We present results from our computer simulations on the photocatalytic water splitting on rutile (110). Our approach consists of a quantum chemical and a quantum dynamical part.
In a first step, we calculated potential energy surfaces (PES) for this system. The surface is made up of a Ti9O18 cluster, saturated by Mg atoms for technical reasons. This cluster is embedded in a large point charge field. This model can describe the adsorption of small molecules successfully on a high level of theory. The bond breaking is a multi-configurational problem. Therefore, CASSCF calculations for the ground state were performed giving a complete (PES) in five dimensions. Furthermore, similar calculations were carried out for an electronically excited state that results from a hole attack on the water. Artificial Neural Networks proofed to be very helpful in fitting these potential energy surfaces without the need of an analytical expression. Both PES are necessary for a real quantum dynamical simulation of photoreactions including quantum effects like tunneling. In the second part of our contribution, we present first results for this kind of simulation based on a jumping wave packet approach. For the first time, the motion of hydrogen after the electronic excitation can be elucidated.
[1] J. Mitschker, T. Klüner, Phys. Chem. Chem. Phys., 2014, DOI: 10.1039/C4CP04593A