ELASTIC-SCATTERING AND THE ASSOCIATED ANOMALOUS-DISPERSION IN THE ATOMIC REGION 3-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-82 AT 30.85KEV

We have measured the differential elastic scattering cross sections in the atomic region 13 less than or equal to Z less than or equal to 82 using nearly monoenergetic unpolarised Cs K alpha (30.85 keV) radiati on at a scattering angle of 90 degrees. Experimental elastic scatterin g cross sections are compared with the theoretical estimates based on form factor formalisms (relativistic, non-relativistic and relativisti c modified form factors). Good agreement is observed between the exper imental results and the theoretical estimates. Form factors were deduc ed using experimental elastic scattering cross sections. Real (f') and imaginary (if '') parts of the anomalous dispersion correction compon ents have been calculated relativistically. Experimental nonanomalous form factors were corrected for anomalous dispersion Experimental resu lts were compared with the theoretical estimates and discussed in orde r to reflect the data on the current knowledge. Deviation of the exper imental form factors above and below the absorption edges, and also ne arer to the edges clearly indicates the need of dispersion corrections .