Scattering of X‐rays near the K absorption edge II. Dispersion factors f′ and f″

The dispersion factors of the X‐ray scattering amplitude, f′ and f″ are studied in the dipole approximation where they are independent of the scattering angle. The imaginary part is proportional to the absorption coefficient, and below the Kedge the observedf″K is in a close agreement with the value calculated from the resonant Raman cross‐section. The real part is calculated from the tabulated absorption coefficients in a number of cases where comparison with direct determinations of f′ can be made. The agreement is good, particularly when extensive data near the edge are available, while recent theoretical values are consistently low. Calculated values of f′ are tabulated for transition elements at several commonly used X‐ray wavelengths.