Answer to Question #143804 in Quantum Mechanics for Sneha

Question

Write notes on natural broadening.

Answer 1

We have been treating the energy levels of atoms, molecules, or ions as if they were sharp distinct states of clearly defined energy. In real practical situations, this is not so, all energy states are smeared out over a finite range of energies. This smearing out of the energy is caused by the uncertainty created during the measurement of energy. This gives rise to an intrinsic and unavoidable amount of line broadening called natural broadening. This uncertainty in measurement energy arises from the time involved in making such a measurement. Natural broadening is the basic form of broadening that would exist even if there were no other form of broadening. It is associated with the finite lifetime of the excited state due to spontaneous emission and can only be rigorously analyzed using quantum mechanics.