Question

I made a solution of fluorscein and diluted it with ethanol, and I was confused about some stuff.

Does emission and excitation depend on concentration?

Would would change if I diluted it with water rather than ethanol?

What is stoke's shift and what is an anti - stoke?

Answer 1

- Emission and excitation DOES depends on concentration

- Emission and exitation depends on concentration and on the type of solvent. Water is similar to ethanol in that it is apolar substance. The hydrogen bonding of both substances make it even similar. Even though they are similar, their specific wavelength will differ since you are using different solvents. You must refer to that specific solvent.

- By definition, the stoke shift is may be described as:

When electrons go from the excited state to the ground state (see the section below entitled Molecular Explanation), there is a loss of vibrational energy. As a result, the emission spectrum is shifted to longer wavelengths than the excitation spectrum (wavelength varies inversely to radiation energy)

For the antistoke shift:

When the emitted photon has less energy than the absorbed photon, this energy difference is the Stokes shift. If the emitted photon has more energy, the energy difference is called an anti-Stokes shift