Physical Basis of Light Absorption by Molecules The Franck-Condon Principle

5 Physical Basis of Light Absorption by Molecules The Franck-Condon Principle 

The total energy of a molecule is made up of its electronic energy and energy of its nuclear (vibrational and rotational) motion. It is expressed as 

the electronic transition by absorption of a photon is often referred to as a vertical transition or Franck-Condon transition. The electronic transition in a 

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