A diagram that represents the electronic energy levels (and their relative positions) of a molecule. A Jablonski diagram enables radiative transitions between energy levels in molecules, as well as such phenomena as internal conversion, to be shown. The vertical axis measures energy, with the electronic energy levels in their lowest vibrational states being short horizontal lines. The vibrational energy levels of a particular electronic state are drawn as shaded regions above the horizontal line for that state. In a Jablonski diagram the horizontal location of the electronic state is not related to the internuclear distance between the atoms in these states.