This effect was the first application of perturbat
This effect was the first application of perturbation theory to quantum mechanics. Aside from regarding the electric field as a perturbation on the quantum states and energy levels of an atom in the absence of an electric field, this effect can also be described by the classical electron theory of Lorentz and Bohr's atomic theory, just like its magnetic field analogue. FTP, identify this counterpart to the Zeeman effect that describes the splitting of atomic spectra due to a strong electric field.
This effect was the first application of perturbation theory to quantum mechanics.
{Stark} effect