Comment on “Mapping photoisomerization dynamics on a three-state model potential energy surface in bacteriorhodopsin using femtosecond stimulated Raman spectroscopy” by Z. Wang, Y. Chen, J. Jiang, X. Zhao and W. Liu, Chem. Sci. , 2025, 16 , 3713

The article by Wang et al. (Chem. Sci., 2025, 16, 3713) reports an experimental study of the photo-isomerization dynamics of the all-trans protonated Schiff base of retinal (AT-PSBR) in bacteriorhodopsin (bR), based on femtosecond stimulated Raman spectroscopy. In the present comment, we point out a misinterpretation of a new interesting high-frequency vibrational mode, conceptual flaws, like interpreting the data in a C2h symmetry framework, and most importantly the neglect of basic properties of AT-PSBR in bR, which were established over the past 30 years. The comment ends with a few suggestions on how to substantiate the new findings within a correct experimental and theoretical framework.