Optical pump - nuclear resonance probe experiments on spin crossover complexes

• Published in: Hyperfine interactions Vol. 238; no. 1; pp. 1 - 7
• Main Authors: Sakshath, S., Jenni, K., Scherthan, L., Würtz, P., Herlitschke, M., Sergeev, I., Strohm, C., Wille, H.-C., Röhlsberger, R., Wolny, J. A., Schünemann, V.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.11.2017; Springer Nature B.V
• Subjects: 3-8 September 2017; Atomic; Condensed Matter Physics; Excitation; Experiments; Forward scattering; Hadrons; Heavy Ions; Lasers; Molecular; Nuclear electric power generation; Nuclear Physics; Optical and Plasma Physics; Physics; Physics and Astronomy; Proceedings of the International Conference on the Applications of the Mössbauer Effect (ICAME 2017); Russia; Saint-Petersburg; Surfaces and Interfaces; Thin Films; Pump-probe experiments; Fe(PM-BiA); Nuclear forward scattering; Spin crossover; Cl; Time-resolved spectroscopy; Fe(NH; ]; trz; NCS
• ISSN: 0304-3843; 1572-9540
• DOI: 10.1007/s10751-017-1461-3

A novel sample environment enabling optical pump – nuclear resonance probe experiments has been installed at the beamline P01, Petra III, DESY Hamburg. This set-up has been used to investigate optically induced spin state changes of spin crossover (SCO) complexes by nuclear resonant scattering immediately after excitation by an optical laser pulse. Here, we report the technical details as well as first results of the experiments performed at 290 K and 80 K on the SCO complexes [Fe (NH 2 trz) 3 ]Cl 2 and [Fe(PM-BiA) 2 (NCS) 2 ], respectively. The 57 Fe-enriched SCO complexes were excited by a 531 nm laser with a pulse length < 100 ps. Evaluation of the nuclear forward scattering data clearly indicate the presence of high spin (HS) states when the complexes are excited by laser pulses and a pure low spin (LS) state in the absence of any laser pulse. Furthermore, the dependence of the optically excited HS-fraction has been determined as a function of the average optical power.