Molecular Spectrometry Techniques

Molecular Spectrometry Techniques

1. Range of techniques separated by;

   • Wavelength of the EMR used
   • Interaction with EMR utilised

2. Typically absorb EMR

3. Techniques use:

   • Transmitted radiation
   • Emitted radiation
   • Interactions
     • Spinning molecular atoms (NMR)
     • Deflecting travel with magnets (MS)

4. UV/Vis Spec

   • EMR absorption of EMR range
     • UV wavelength
     • Visible wavelength
     • Technique is colourimetry
       • Absorbance in visible range
       • Used everyday
       • Colours identify objects
   • Excitation of electrons in bonds
     • Changes position of electrons in bond
     • Very briefly
   • Simplest methods and super cheap

5. FTIR & Raman Spectroscopy

   • Molecular excitation
     • Bond vibrations
       • Vibrations include various forms of stretching & bending
       • As electrons are getting excited
   • Bonds between different atoms
   • Absorb different wavelengths of radiation
     • Different bonds & masses of atoms
   • Used to identify bonds present
   • Laser infused

6. Bond vibrations

   • Bending
     • Scissor bending
     • Rocking
     • Wagging
     • Twisting
   • Stretching
     • Symmetrical stretching
     • Asymmetrical stretching