Theoretical backscattering amplitude and phase functions, B(k) and φ(k), used in extended x-ray-absorption fine structure (EXAFS) studies show strong features in their k dependence which can be identified as a ‘‘generalized Ramsauer-Townsend effect.’’ This effect is studied in detail for elements with atomic number 78≤Z≤90.

• Received 4 April 1988

DOI:https://doi.org/10.1103/PhysRevB.38.10919