Hello. What is troubling me is I can't stabilish a connection. and it seems to be it should exist, between the polarization of a material by displacement of the electron cloud and energy level transition in a molecule or solid. When an electric field is applied to a material, the "electronic cloud" distribution is modified. So, I wonder how can this be connected to the quantum nature of the energy levels of electrons in solids or molecules. I think such a connection might exist because when the electronic distribution is modified, the wave function must be in some way affected and so this could be related to electronic transitions between energy levels of the material. What do you think? Can you offer some explanation or indicate o good reference? Thanks in advance.