A graph of the potential energy of electrons in a diatomic molecule, in which the potential energy of an electronic state is plotted vertically and the interatomic distance is plotted horizontally, with the minimum of the curve being the average internuclear distance. The Morse potential gives a good analytic description of a potential-energy curve. The dissociation energy and certain quantities of interest in vibrational spectroscopy can be found from the potential-energy curve.