Primer on Coupling Collective Electronic Oscillations to Nuclei

On the basis of simple heuristic models, we show that atomic electrons can (1) amplify fields observed at the nucleus, (2) generate harmonics, and (3) drive higher multipolarities. We consider a model with the nucleus at the focus of a uniformly charged ellipsoid. It amplifies an oscillating external electric field and produces an oscillating electricfield gradient but no higher derivatives. The electric field has only odd harmonics and the electric-field gradient has only even harmonics. There is an optimum intensity for driving each harmonic. We comment on the relevance of these results to the U experiment and to the gamma-ray laser.