Excited-state dynamics of carotenoids in light-harvesting complexes. 1. Exploring the relationship between the S(sub 1) and S(super *) states

Excitation-intensity-dependent pump-probe (PP) measurements have helped in gaining insight into the light-induced dynamics of the light-harvesting 2 (LH2) complex isolated from Rhodopseudomonas acidophila. The S(super *) state has exhibited a different response to the increase of excitation intensity than S(sub 1) state and hence two new models that can describe both the time-resolved and the intensity-dependent data are proposed.