In a fluorescence-lifetime experiment, a very short pulse of light is used to excite a sample. Then
Question:
In a fluorescence-lifetime experiment, a very short pulse of light is used to excite a sample. Then the intensity of the fluorescence is recorded as a function of time. Suppose we study a dansyl fluorophore. The intensity of the fluorescent light versus time is as follows:
Fluorescence intensity | Time (ns) |
1.1 X 104 | 0 |
4.9 X 103 | 5 |
2.3 X 103 | 10 |
1.3 X 103 | 15 |
5.6 X 102 | 20 |
a. what is the observed fluorescence life time?
b. The fluorescence quantum yield under the same conditions was determined to be 0.7. What is the intrinsic rate constant for radiative fluorescence decay?
c. It has been determined separately that when the dansyl chromophore is 20 A away from the 11-cw-retinal chromophore in rhodopsin, the efficiency of fluorescence energy transfer is 50%. In a second experiment, rhodopsin is covalently labeled with a dansyl chromophore and the observed fluorescence lifetime for the dansyl-rhodopsin complex is 6 ns. What is the distance between the dansyl label and the retinal chromophore in rhodopsin?
College Physics
ISBN: 978-0495113690
7th Edition
Authors: Raymond A. Serway, Jerry S. Faughn, Chris Vuille, Charles A. Bennett