Excited-state properties of biliproteins: I. Phytochrome Pr

摘要

Phytochrome Pr has been investigated by means of picosecond intensity-dependent transmission measurements at several excitation wavelengths inside the S_0->S_1 absorption band. The experimental data exhibit relatively strong excited-state absorption (ESA) within the whole spectral range of the S_0->S_1 absorption, which is followed by fast relaxations on the femtosecond time scale (<200 fs). The ESA cross sections at wavelengths below 640 nm are lower than those of the ground-state absorption, but they are noticeably larger at the maximum and at the long-wavelength side where stimulated emission additionally influences the bleaching behaviour. The spectral characteristics of the emission cross sections have been shown to be a good measure for the correct radiative lifetime #UPSILON#_0. This confirmed our recently published value of #UPSILON#_0=4.9 ns.