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The more intense infrared absorption for H2O is observed at 3300 cm-1..?
The more intense infrared absorption for H2O is observed at 3300 cm-1.
1) Assuming that the vibration mode at 3300 cm-1 is also active in Raman spectroscopy, calculate the wavelength of the Stokes Raman line length observed (in nm) by deduction knowing that the fluorescence spectrum of the excited state of water is at λ = 390 nm
Could some one please explain what transitions are taking place for each of the three cases before explaining the answer. Thank you
1 Answer
- ?Lv 77 years agoFavorite Answer
"... please explain what transitions are taking place for each of the three cases ..."
I am not sure what the "three cases" are.
The IR- and/or Raman-activity of a vibrational mode in a molecule.is dictated by rules in group theory and is beyond the scope of YA to answer completely. (a basic treatment of Raman scattering can be found on Wikipedia:
http://en.wikipedia.org/wiki/Raman_scattering)
The calculation that is required for the Stokes line uses the equation
ν(Raman) = ν(incident) - ∆ν
(Galen W. Ewing, Instrumental Methods of Chemical Analysis, McGraw-Hill, 1975, p 142)
ν(Raman) = (1/(390 x 10^-7 cm)) - 3300 cm^-1
ν(Raman) = 25641 cm^-1 - 3300 cm^-1 = 22341 cm^-1
Now we convert that frequency back to wavelength in nm:
1/22341 cm^-1 = (4.476 x10^-5) x 10^7 nm = 447.6 nm
