Transient absorption changes of a degenerate dimer induced by exciton scattering; implications for Photosystem II of photosynthesis Original Research Article

The effect of exciton scattering on transient absorption spectra of a degenerate dimer has been calculated from a simple four-level model. The absorbance changes due to this scattering process not only depend on the polarization of the probe beam, but also on the selectivity of excitation of specific exciton components. In the case of selective excitation, the absorbance changes induced by exciton scattering may play an important role in time-resolved spectroscopy of the reaction center of Photosystem II at short times after excitation.