Pre-Assignment

1. Why is dynamic quenching mechanism not operative in rigid systems?
2. "Fluorescence of compounds of long lifetime, such as naphthalene and pyrene, are particularly sensitive to the presence of oxygen." Why?
3. Mention one method by which oxygen quenching can be avoided.
4. Will the mean fluorescence life time measured in the presence of dynamic quenching be different from that measured in the absence of the quenching? Why?
5. How will the fluorescence life time be affected in static quenching?
6. "Dynamic quenching increases with temperature." Why?

Post-Assignment

1. Why is anthracene faint yellow in color?
2. How many gram of anthracene is required to make a 2.0 * 10^-3 M anthracene solution in 100 mL ethanol?
3. Neglecting the volume of pyridinium chloride added with respect to the volume of anthracene solution, calculate the total concentrations of pyridinium chloride in the solution after each addition.
4. Calculate the % increase in volume due to the additions of the quenching solution to the original solution. Discuss how this dilution effect will affect the concentrations of the quencher.
5. What is unit of K_SV?
6. How is the quantity, (F₀/F - 1) / [Q], independent of quencher concentration for dynamic quenching?
7. How is KSV related to the quenching concentration at 50% quenching?
8. What does it suggest when k_q and the diffusion controlled rate constant, k_d, have similar values?