** Next:** 1. Introduction

# Comparison of relativistic partial wave calculations of
triply differential electron-atom bremsstrahlung with simpler
theories

**C. David Shaffer**^{*}, R. H. Pratt

Department of Physics and Astronomy, University of Pittsburgh,
Pittsburgh, Pennsylvania 15260

### Abstract:

The results of our exact partial wave triply differential
electron-atom bremsstrahlung calculations are compared with those of
simpler theories. This triply differential cross section is expected
to provide a more sensitive test of the adequacy of theoretical
descriptions of the process than the doubly differential cross
section, not observing the scattered electron. Our method is an
extension and reformulation of the relativistic partial wave and
multipole decomposition method of Tseng and Pratt, which was only used
to calculate the doubly differential cross section. We compare our
calculations to those using the Bethe-Heitler equation (first Born
approximation including form factors) and to calculations using the
formalism of Elwert and Haug (which utilize approximate Coulomb wave
functions and form factors). We examine silver and heavier elements,
where the validity of the simpler theories is in question. For such
elements we find no significant region of agreement with the
Bethe-Heitler theory. We find some agreement with the theory of
Elwert and Haug at small momentum transfers, improving with increasing
energy. We find poor agreement of our results with the Elwert-Haug
results for large momentum transfers. The differences from simpler
theories are indeed much greater in the triply differential cross
section than in the double differential cross section.

** Next:** 1. Introduction
*Eoin Carney*

*1999-06-14*