On Nuclear Dipole Vibrations

Abstract

The high frequency resonances recently observed for ($\gamma ,n$) reactions as well as photo-fission are interpreted in analogy with the "reststrahl frequencies" of polar crystals. The estimated frequencies are in good agreement with the experimental results. An interesting consequence of this interpretation is the conclusion that strong resonance scattering of $\gamma$-rays should take place at a frequency characteristic of the scattering nucleus.