ABSTRACT
Core polarization may well play a more important role in determining the ion-ion interaction; however, this effect can be included approximately in the ion-ion potential. The hyperfine and electron spin-spin interactions will also be neglected for the moment; the former were treated as a perturbation when we considered nuclear-spin relaxation processes. The bare electron–phonon interaction is of the conventional form for a boson-fermion coupling, that is, linear in the boson field, bilinear in the fermion field. When external fields and/or net currents exist there is a coherent addition of the fluctuating magnetic fields between electrons; the resultant field can be conveniently treated within a self-consistent field approximation and fluctuations about the average field neglected. The bare phonons are quantized vibrations of the jelly. In this "jellium" model, the bare electron–phonon interaction is easily calculated and one finds for longitudinal phonons.
