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

Abstract

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 C_2h 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.