2. Given the 4 level photophysical-system mentioned during the lecture, with a singlet ground state, singlet excited state, triplet excited state, dark state, and respective rate constants (defined in lecture and shown on the diagram below), determine: a. the fluorescence emission rate, F, dependence on the other parameters in a single equation and graph the fluorescence emission rate dependence on the excitation intensity, / (i.e., fluorescence emission rate, F, on the y-axis and excitation intensity, I, on the x-axis) b. the maximal fluorescence emission rate when the excitation intensity approaches infinity (i.e., when /→ ∞, F=?) c. the saturation intensity, Is no Kerans ko $0 n k = ol ng 2 Kisc n

Fig: 1