Improvements in computation of form factors

Abstract

Tables for form factors and anomalous dispersion are of wide general use in the UV, X-ray and γ-ray communities,and have existed for a considerable period of time. The generality of these works has entailed numerous simplications compared to detailed relativistic S-matrix calculations. However, the latter calculations do not appear to give convenient tabular application for the range of Z and energy of general interest, whereas the former tables have large regions of limited validity throughout the range of Z and energies, and in particular have limitations with regard to extrapolition to energies outside tabulated ranges. Intermediate theoretical and procedural assumptions limit the precisi..