Pre-Assignment

1. In fluorescence, generally the state from which the system decays is independent of the excitation wavelength. Why?
2. What happen to the energy of the excited state and the emission spectrum when re-organization of solvent dipoles occurs around the excited fluorophore?
3. Compare the effects of increase in refractive index and dielectric constant on the ground and excited state energies.
4. The Lippert-Mataga equation tends to give greater than the predicted Stokes shifts for protic solvents like water and alcohols. Why?
5. When the solvent has no permanent dipole moment, how n is related to ε and what is the value of λf?

Post-Assignment

1. How many grams of curcumin should one dissolve in a given solvent to prepare a 100 mL 1x10-3M stock solution?
2. In Lippert-Mataga plots, groups of solvents with similar chemical nature often tend to cluster. Why?
3. If one obtains a positive slope in the Lippert-Mataga plot, is the excited state more polar or less polar than the ground state?
4. In the Lippert-Mataga plot, does the point corresponding to methanol lie above or below the straight line fit? What could be the possible reason for this?
5. What do the steady state spectral measurements of curcumin suggest about the polarity of the S1 state with respect to its S0 ground state?