High frequency limit of bremsstrahlung

It is shown that, contrary to common belief, the bremsstrahlung cross section vanishes at the high frequency limit for a neutral atom. The Sommerfeld finite value at the upper limit is valid only for atomic fields falling off as r-1 for large distances, i.e., for ionized atoms. The behavior of the cross section at the high frequency limit is closely connected to the number of bound states close to the continuum limit for the atom. An explicit calculation is performed for a particular screened atomic field. (Auth)