Pre-Assignments

1. Why do polar solvents obliterate the fine spectral structures in an absorption band?
2. In which state is a molecule generally more polar - when (i) pi molecular orbital is full or (ii) one pi electron is excited to pi antibonding molecular orbital?
3. Which solvent between cyclohexane and ethanol has higher dipole moment?
4. When a chromophore binds to proteins, the binding site is generally more hydrophobic than the solution. Then, what kind of shift do you expect to observe in the absorption peak position compared to the peak observed when the chromophore is free in solution?

Post-Assignments

1. What are the cut-off wavelengths for the solvents used in this experiment?
2. Do you observe any change in the form of the absorbance bands while moving from nonpolar to polar solvents?
3. What kinds of possible electronic transitions do you expect to observe in coumarin-138?
4. Which parameter between "solvent polarity function" and dielectric constant show better correlation with the peak positions?