Excited-State Dynamics of Carotenoids Studied by Femtosecond Transient Absorption Spectroscopy

Abstract

Carotenoids, natural antenna piginents in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-beta-caroten-8'-al and 7',7'-clicyano-7'-apo-beta-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-beta-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the S-2 and S-1 excited states.