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CH3041
MOLECULAR SPECTROSCOPY
• 2 common forms of molecular absorption
spectroscopy are UV-Vis and IR.
spectroscopy are UV-Vis and IR.
• Ephoton = h c / l (wavelength l in nm)
= Emolecule-highEstate - Emolecule-lowEstate
• UV-Visible
absorptions occur between
high lying occupied MOs and low lying
unoccupied MOs - electronic spectroscopy
high lying occupied MOs and low lying
unoccupied MOs - electronic spectroscopy
• Infra Red
absorptions occur between mol. vibrational states - vibrational spectroscopy
• In both cases a characteristic wavelength
is selected for the analyte & the intensity of this absorption is then related to the conc.
is selected for the analyte & the intensity of this absorption is then related to the conc.
