On the constitution of atoms and molecules

by Niels Bohr

. Using the same notation as above, we get

If all the electrons in one of the rings are displaced in the same direction by help of extraneous forces, the displacement will produce corresponding displacements of the electrons in the other rings; and this interaction will be of influence on the stability. For example, consider a system of

concentric rings rotating in a plane round a nucleus of charge

, and let us assume that the electrons in the different rings are displaced perpendicular to the plane by

,