Conical intersection dynamics in a rhodopsin analog: 9-cis isorhodopsin

none8Light perception is based on a cascade of complex biochemical reactions whose first step is the ultrafast (completed in ≈200 fs) and efficient (0.65 quantum yield) isomerisation of the retinal chromophore of rhodopsin around the 11=12 double bond from the 11-cis to the all-trans form (Fig. 1) [1]. It is now well established that rhodopsin's unique reactivity is mediated by conical intersections (CIs), i.e. singularities on the potential energy surfaces (PES) that form a multi-dimensional seam connecting the ground and excited states at isoenergetic points [2]. CIs are ubiquitous features in theoretical descriptions of organic photochemistry and are responsible for triggering radiationless decay and efficient and ultrafast conversion of photon energy into chemical energy.noneD. Polli;D. Brida;C. Manzoni;K. M. Spillane;M. Garavelli;P. Kukura;R. A. Mathies;G. CerulloD. Polli;D. Brida;C. Manzoni;K. M. Spillane;M. Garavelli;P. Kukura;R. A. Mathies;G. Cerull