Chapter 11, Problem 11.5PR

Interpretation Introduction

Interpretation:

Distance in which two chlorophyll a gets separated has to be determined.

Concept Introduction:

Ratio of the fluorescence quantum yields in presence and absence of the quencher (Q) can be determined as follows,

$\begin{array}{c}\frac{{\varphi }_{\text{F}}}{{\varphi }_{\text{F,0}}}\text{ = }\frac{\text{τ}}{{\text{τ}}_{\text{0}}}\\ \\ where,\\ {\varphi }_{\text{F,0}}\text{ = Fluorescence quantum yield in absence of Q}\\ {\varphi }_{\text{F}}\text{ = Fluorescence quantum yield in presence of Q}\\ {\tau }_0\text{ = Observed fluorescence lifetime in absence of Q}\\ \tau \text{ = Observed fluorescence lifetime in presence of Q}\end{array}$

According to the Förster theory, the donor–acceptor distance (R) can be determined in terms of efficiency of transfer as follows,

  $R{\text{= R}}_0{\left(\frac{1-{\eta }_T}{{\eta }_T}\right)}^{\text{1/6}}$

Efficiency of transfer can be determined in terms of presence and absence of the quencher as follows,

  ${\eta }_T\text{= }\frac{{\varphi }_{F,0}-{\varphi }_F}{{\varphi }_{F,0}}\text{ = 1}-\frac{{\varphi }_F}{{\varphi }_{F,0}}$