The electronic state
manifolds of carotenoids and their relaxation
dynamics are the object of intense investigation because most of the
subtle details regulating their photophysics are still unknown. In
order to contribute to this quest, here, we present a solvent-dependent
2D Electronic Spectroscopy (2DES) characterization of fucoxanthin,
a carbonyl carotenoid involved in the light-harvesting process of
brown algae. The 2DES technique allows probing its ultrafast relaxation
dynamics in the first 1000 fs after photoexcitation with a 10 fs time
resolution. The obtained results help shed light on the dynamics of
the first electronic state manifold and, in particular, on an intramolecular
charge-transfer state (ICT), whose photophysical properties are particularly
elusive given its (almost) dark nature.