Spin-Crossover-Systems are metal complexes, which exhibit two (meta)-stable states, one with a low and one with a high spin. The transition between these states is usually driven thermally, in solid state also by change of pressure. In several systems this transition can also be triggered by photoactivation. This transition is already known to occur on an ultrafast time-scale. Femtosecond infrared and visible spectroscopy is used to investigate the spin-crossover and associated processes.
In collaboration with the group "Biophysik und Medizinische Physik" of Prof. Volker Schünemann (TU Kaiserslautern) we investigate selected spin-crossover systems like [Fe(btpa)]2+ or [Fe(b(bdpa))]2+.