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

✍ Scribed by Remedios González-Luque; Gloria Olaso-González; Manuela Merchán; Pedro B. Coto; Luis Serrano-Andrés; Marco Garavelli

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 244 KB
• Volume: 111
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/qua.23079

✦ Synopsis

Abstract

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