Question

3) What is Rayleigh scattering? Given an excitation wavelength of 350 nm and an aqueous solution, at what wavelengths would you expect to see the Rayleigh scattering peaks in the emission spectrum?

4. Why are anti-Stokes shifts the least common phenomenon compared to Stokes or Rayleigh scattering?

Answer 1

3) RAYLEIGH SCATTERING

a / It is elastic scattering of light or other electromagnetic radiation by particles ( much smaller than the wavelength of light / radiation ) in a medium without change in wavelength .

Rayleigh scattering refers to radiation scattered in all directions by elastic collisions ( impinging and dispersed radiations are of the same wavelength and are related in a random manner )

The process of Rayleigh scattering accounts for the blue color of sky , since the blue light is scattered slightly more efficiently than the red.

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When an aqueous solution excited at wavelength of 350 nm the Rayleigh excitation peaks appear at 450 nm in its emission spectrum.

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4 . Antistoke shifts are the least common phenomenon as it requires the molecule to be in vibrationally excited state before photon is incident upon. Further due to lack of intensity of the antistoke signal and necessity of the filtering requirements that eliminates photon with incident energy ,generally stoke scattering is preferred.

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