1. Femtosecond Spin-State Switching Dynamics of Fe(II) Complexes Condensed in Thin Films
- Author
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Kämmerer, Lea, Kämmerer, Gérald, Gruber, Manuel, Grunwald, Jan, Lojewski, Tobias, Mercadier, Laurent, Le Guyader, Loïc, Carley, Robert, Carinan, Cammille, Gerasimova, Natalia, Hickin, David, Van Kuiken, Benjamin E., Mercurio, Giuseppe, Teichmann, Martin, Kuppusamy, Senthil Kumar, Scherz, Andreas, Ruben, Mario, Sokolowski-Tinten, Klaus, Eschenlohr, Andrea, Ollefs, Katharina, Schmitz-Antoniak, Carolin, Tuczek, Felix, Kratzer, Peter, Bovensiepen, Uwe, and Wende, Heiko
- Abstract
The tailoring of spin-crossover films has made significant progress over the past decade, mostly motivated by the prospect in technological applications. In contrast to spin-crossover complexes in solution, the investigation of the ultrafast switching in spin-crossover films has remained scarce. Combining the progress in molecule synthesis and film growth with the opportunities at X-ray free-electron lasers, we study the photoinduced spin-state switching dynamics of a molecular film at room temperature. The subpicosecond switching from the S= 0 low-spin ground state to the S= 2 high-spin state is monitored by analyzing the transient evolution of the Fe L3X-ray absorption edge fine structure, i.e. element-specifically at the switching center of the Fe(II) complex. Our measurements show the involvement of an intermediate state in the switching. At large excitation fluences, the fraction of high-spin molecules saturates at ≈50%, which is likely due to molecule–molecule interaction within the film.
- Published
- 2024
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