Question

4. For phenanthrene, the measured lifetime of the triplet state is 5 = 3.3 s. The measured lifetime of the singlet state is = 34 ns. The fluorescence quantum yield is 4 -0.12 and the phosphorescence quantum yield i 0.13. Assume that no collisional quenching and no internal conversion from the excited singlet state S, occurs. Determine the fluorescence rate constant k, and the rate constant for intersystem crossing from the excited singlet state to the triplet state . Also determine phosphorescence rate constant kp, the rate constant for intersystem crossing back to the ground electronic state S0 from the triplet state

Answer 1

ab loh sKi dia singlet- チ SC Scee hos pho nescence -呂 5ince there is no inten Gvesi 4 gaenching kes -is given below.一 6 The sate onstant for iner yotem m e te C 外e exciteaf sing let state ,totte -tsi plet stede 15c ISC 6 6 012 (23-41-3. 53) = )。 6

中 7p 0-13 2-3S 2 2--te Constand-of DSc (T. VTP ISc 3. 93 x10 0.13 (30. 2.3 x 102) _ (393 x 102 ) 30.23 × 10 2.63×10 0- 263 s