It is mentioned in the explanation of the dielectric properties of nanoparticles that all four types of polarization can occur even at low frequencies,but to what extent is the movement of the electron cloud at these frequencies physically reasonable?Isn't this related to the relaxation process? For example, suppose the relaxation time of electronic polarization is 1 second(I know it is not so), but the electric field changes every 5 seconds — in that case, wouldn't electric polarization still occur? I find it difficult to visualize this.I would appreciate it if you could provide a reference explaining this.