Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 40: Spin Effects in Molecules at Surfaces (jointly with DS, MA)
O 40.8: Vortrag
Mittwoch, 13. März 2013, 11:30–11:45, H23
Spin Crossover in a Vacuum-Deposited Submonolayer of a Molecular Iron(II) Complex — •Matthias Bernien1, Dennis Wiedemann2, Christian F. Hermanns1, Alex Krüger1, Daniela Rolf1, Wolfgang Kroener3, Paul Müller3, Andreas Grohmann2, and Wolfgang Kuch1 — 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — 2Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany — 3Department of Physics, Universität Erlangen-Nürnberg, Erwin-Rommel-Straße 1, 91058 Erlangen, Germany
Spin-state switching of transition-metal complexes (spin crossover) is sensitive to a variety of tiny perturbations. It is often found to be suppressed for molecules directly adsorbed on solid surfaces. We present X-ray absorption spectroscopy measurements of a submonolayer of [FeII(NCS)2L] (L: 1-{6-[1,1-di(pyridin-2-yl)ethyl]-pyridin-2-yl}-N,N-dimethylmethanamine) deposited on a highly oriented pyrolytic graphite substrate in ultrahigh vacuum. These molecules undergo a thermally induced, fully reversible, gradual spin crossover with a transition temperature of T1/2 = 235(6) K and a transition width of Δ T80 = 115(8) K. Our results show that, by using a carbon-based substrate, the spin-crossover behavior can be preserved even for molecules that are in direct contact with a solid surface.
Financial support by the DFG (Sfb 658: Elementary Processes in Molecular Switches on Surfaces) is gratefully acknowledged.