A first detection of singlet to triplet conversion from the 11Bu− to the 13Ag state and triplet internal conversion from the 13Ag to the 13Bu state in carotenoids: dependence on the conjugation length

Excited-state dynamics of the 1Bu+,3Ag−, and 1Bu− states in a carotenoid molecule by 5-fs absorption spectroscopy

“…The third appearing in the sequence is the difference spectrum, which is found typically at 65 fs, consists of a pair of negative signals ascribable to the vibrational progression of the 1B þ u stimulated emission and a broad transient absorption centered around 620-680 nm. This spectral pattern can be assigned to the 1B À u state based on spectral comparison with the difference spectral pattern reported previously [10]. The fourth in the time sequence of difference spectrum at 220 fs consists of the bleaching of the 1B þ u ð0Þ 1A À g ð0Þ stationary absorption and a strong transient absorption peaked at 615 nm.…”

The energies and kinetics of triplet carotenoids in the LH2 antenna complexes as determined by phosphorescence spectroscopy

“…1 3 A g (T 2 ) followed by the triplet internal conversion of 1 3 A g (T 2 ) ! 1 3 B u (T 1 ) [6]. The 1 1 B À u !…”

“…Depending on the major function, two different kinds of configurations have been selected by the pigment-protein complexes: all-trans Cars are selectively bound to the antenna complexes, while 15-cis Cars to the reaction center [2,3]. In order to reveal the mechanisms of the light-harvesting and the photoprotective functions, the energies and kinetics of excitedstate Cars are key factors to be determined: Concerning the singlet-excited states, a set of four different low-lying singlet-excited states, including 1 1 B þ u , 1 1 B À u , 3 1 A À g and 2 1 A À g , were identified [4], and their relaxation pathways and decay time constants have been determined [5,6]. However, the energies of the triplet-excited states remain to be determined, although the lifetimes of the lowest triplet (T 1 1 3 B u ) state have been determined free in solution and bound to the pigment-protein complexes [7].…”

Ultrafast Energy‐Transfer Pathway in a Purple‐Bacterial Photosynthetic Core Antenna, as Revealed by Femtosecond Time‐Resolved Spectroscopy

“…The Spx!Bchl EET processes of Rsp. rubrum S1 after excitation into S 2 of Spx have been reported previously [12][13][14] (see also the Supporting Information); therefore, we focused our attention on the dynamics of reverse Bchl!Spx EET after excitation into the Q x band of Bchl. We recorded a set of photoinduced absorption spectra of the chromatophores of Rsp.…”

“…In these bacterial light-harvesting complexes, the reported efficiency of S 2 !Q x EET is approximately 30 %, whereas that of S 1 !Q y EET is 0 %. [12][13][14] We recorded steady-state absorption spectra of the chromatophores of Rsp. rubrum S1, the corresponding carotenoidless mutant, Rsp.…”