Ultrafast multichromophore excited-state dynamics of luteins in the sites L1 and L2 in trimeric LHCII. Populations of adiabatic localized excitations a and diabatic states b as functions of time obtained from the SH dynamics with the Frenkel exciton model, divided according to the initial excitation either on L1-Lut (left) or L2-Lut (right). The reported results are obtained by averaging over all trajectories (monomer M2) and time intervals of 0.1 fs.

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... on the dipole transition probability from the ground-state [39], within the excitation energy range of 2.70 ± 0.15 eV for L1-Lut and 2.65 ± 0.15 for L2-Lut. These energy ranges include most of the main band of the absorption spectrum of the corresponding lutein in LHCII trimer, computed along the QM/MM thermal equilibrations (see Fig. S3 and Fig. S4) In the SH simulations, we employed Tully's "fewest switches" algorithm [23], using a locally diabatic representation for the time evolution of the electronic wave function [36]. To account for quantum decoherence effects, we used the overlap decoherence correction (ODC) scheme [40], with the following parameters: σ = 1.0 a.u. (Gaussian ...

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... states is negligible, we can separate the SH trajectories where L1-Lut is initially excited from those with initial excitation of L2-Lut. This procedure also allows us to mimic experimental conditions where each lutein in LHCII is selectively excited. [21] The state population dynamics obtained from these two sets of SH trajectories are shown in Fig. ...

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... L1-Lut is excited (Fig. 4, panels a and b, left), most of the population dynamics involves the excited states of L1-Lut. In particular, in the adiabatic basis (Fig. 4a, left), we observe an initial exchange of population between S 2 and S 3 of L1-Lut, which is followed by the decay of these two states mainly to the lower-lying S 1 state of the same chromophore. ...

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... L1-Lut is excited (Fig. 4, panels a and b, left), most of the population dynamics involves the excited states of L1-Lut. In particular, in the adiabatic basis (Fig. 4a, left), we observe an initial exchange of population between S 2 and S 3 of L1-Lut, which is followed by the decay of these two states mainly to the lower-lying S 1 state of the same chromophore. In the diabatic basis (Fig. 4b, left) dynamics is obtained when L2-Lut is excited (Fig. 4, panels a and b, right), confirming negligible differences ...

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... b, left), most of the population dynamics involves the excited states of L1-Lut. In particular, in the adiabatic basis (Fig. 4a, left), we observe an initial exchange of population between S 2 and S 3 of L1-Lut, which is followed by the decay of these two states mainly to the lower-lying S 1 state of the same chromophore. In the diabatic basis (Fig. 4b, left) dynamics is obtained when L2-Lut is excited (Fig. 4, panels a and b, right), confirming negligible differences between the ultrafast S 2 decay of both luteins. Indeed, for both L1-Lut and L2-Lut excitations, the time evolutions of the populations computed with the excitonic approach are qualitatively very similar to those we obtained ...

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... states of L1-Lut. In particular, in the adiabatic basis (Fig. 4a, left), we observe an initial exchange of population between S 2 and S 3 of L1-Lut, which is followed by the decay of these two states mainly to the lower-lying S 1 state of the same chromophore. In the diabatic basis (Fig. 4b, left) dynamics is obtained when L2-Lut is excited (Fig. 4, panels a and b, right), confirming negligible differences between the ultrafast S 2 decay of both luteins. Indeed, for both L1-Lut and L2-Lut excitations, the time evolutions of the populations computed with the excitonic approach are qualitatively very similar to those we obtained for the two separate luteins (Section 3.2, (Fig. 3). ...

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... the other hand, it is worth noticing that, in agreement with the SH singlechromophore simulations discussed in Section 3.2, the SH excitonic model confirms the formation of the 1B − u (S x ) dark state for both luteins in the sites L1 and L2 (see Fig. 4b). Therefore, we can conclude from our calculations that the formation of the S x dark state in LHCII is not exclusive to the L2 site, but is also present in ...