Figure 1

Mössbauer spectra showing the absorption of the high and low-spin states at (a) room temperature (20 \(^\circ \)C), (b) at 30 \(^\circ \)C, (c) after heating to 57 \(^\circ \)C and (d) after cooling to 30°. The spectra are taken in transmission configuration as function of the modulation of the gamma ray emitter given in mm/s.