Fig. 7
From: Three-dimensional view of ultrafast dynamics in photoexcited bacteriorhodopsin
Temporal evolution of the apparent C13=C14 retinal torsion angle. The structural dynamics of the twisting bond can be divided into three distinct phases (a). b The first (I, 0–~500 fs, yellow) reflects the initial torsional motion in S1 after relaxation from multiphoton excited high energy states Sn and internal conversion into S0. c During the second phase (II, ~500–750 fs, beige), the torsion angle decreases, indicating transition not only to the hot J state but also to a hot all-trans ground state. The small reduction of the dihedral angle is due to an average over the populated vibrationally hot distorted S1, the 13-cis J state and the all-trans ground state. The 0.5–0.8 ps timescale is consistent with the decay of the excited state (cf. “spectroscopic characterization”). This is followed by phase III (1–10 ps, pink, d) displaying the increase of the torsion angle, as expected for J and K state relaxation, ultimately yielding the relaxed 13-cis isomer of retinal. The error bars were derived as described in Supplementary Methods. Source data are provided for Fig. 7a as a Source Data file
