Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 75: Metal substrates: Adsorption of organic / bio molecules VIII

O 75.3: Talk

Thursday, March 17, 2011, 15:30–15:45, PHY C213

Isomerization Dynamics of Adsorbed Molecular Switches: A ΔSCF Density-Functional Theory Study — •Reinhard J. Maurer and Karsten Reuter — Department Chemie, Technische Universität München

Stabilizing molecules at solid surfaces and switching them reversibly between defined states would be a key component of a future molecular nanotechnology. Adsorption at metal surfaces is of particular interest as it could lead to novel functionality in form of isomerization mechanisms not present in gas-phase or solution. Recent experiments indeed suggest such a photo-induced mechanism for tetra-tert-butyl functionalized azobenzene (TBA) at Au(111) [1], involving electron transfer from the molecule to a photo-excited hole in the metal d-band.

Addressing this suggestion with first-principles modeling requires a numerically highly efficient approach to make the calculations of photo-excited molecular motion at the extended surface tractable. To this end we explore a density-functional theory based Delta self-consistent field approach and assess its reliability for a test set of small, related molecules against higher-level theory. Obtaining encouraging results we proceed to a discussion of azobenzene and TBA in excited states corresponding to the suggested hole-mechanism. [1] S. Hagen et al., J. Chem. Phys. 129, 164102 (2008).