•Basic quantum mechanics requires that molecules absorb energy as quanta (photons) based upon a criteria specific for each molecular structure
•Absorption of a photon raises the molecule from ground state to an
excited state
•Total energy is the sum of all components (electronic, vibrational, rotational, translations, spin orientation energies) (vibrational energies are quite small)
•The structure of the molecule dictates the likely-hood of absorption of energy to raise the energy state to an
excited one
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