Fig. 4: Structural dynamics groups and temporal evolution.
a Structures of the molecule in the LS state (in the LT unit cell) (blue smooth lines) and in the HS state (converted into the same LT unit cell) (red fluted lines). The two structures overlap by their iron centers to better display the molecular structural changes occurring upon SCO. The atomic motions in 1 are decomposed into two structural dynamics groups schematized by arrows: symmetric Fe−ligand elongation with the rigid ligands (pELO) and ligand rotation toward the HS structure (pROT), b Temporal evolution of the Fe−ligand distance (average length of the Fe−N coordination bonds, green open circles) and of the ligand rotation (average N−Fe−N angles, purple open circles) in the ultrafast timescale (from −1 to + 2 ps). Solid lines show the fitting curves using multi-exponential decay functions (Supplementary Eq. 2). Horizontal dashed lines correspond to the structural parameters in the HT phase (373 K) and LT phase (300 K), respectively. Error bars represent the full-width at half-maximum (FWHM) of the global maximum peaks of the Pearson correlation coefficient in reaction coordinate space (Supplementary Fig. 5).
