Detalle de: On the role of the triplet state in the cis / trans isomerization of rhodopsin: A CASPT2//CASSCF study of a model chromophore

The possibility of population of the lowest‐lying triplet state ( T 1 ) in the early events of the photochemical isomerization process of a model chromophore of Rhodopsin (Rh) has been analyzed using multireference perturbation theory (CASPT2//CASSCF) methods. It is shown that the characteristics of the isomerization process namely small S 1 − T 1 gap, presence of hydrogen out of plane active vibrational modes, and existence of a dense manifold of vibrational states, render possible the fulfilment of the conditions needed for the population of T 1 . The possible consequences for the photochemistry and photophysics of Rh are also discussed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem 111:3431–3437, 2011