Excited state dynamics of the astaxanthin radical cation

The dynamics of the radical cation proved to be more complex. The main absorption band was shifted to 880 nm (D0 → D3 transition), showing a weak additional band at 1320 nm (D0 → D1 transition). We found, that D3 decays to the lower-lying D2 within 100 fs, followed by a decay to D1 with a time constant of 0.9 ps. The D1 state itself exhibited a dual behavior, the majority of the population is transferred to the ground state in 4.9 ps, while a small population decays on a longer timescale of 40 ps. Both transitions from D1 were found to be fluorescent.