real and imaginary dispersion corrections for elements using Co K-alpha radiation

Dear all, During reitveld refinement of XRD data using LS1, for Cobalt K-alpha radiation, it asks the real and imaginary parts of the dispersion correction(f' and f"). Can any one help me by suggesting some database suitable for LS1, which consits the real and imaginary dispersion corrections f

real and imaginary dispersion corrections for elements using Co K-alpha radiation

Dear all, During reitveld refinement of XRD data using LS1, for Cobalt K-alpha radiation, it asks the real and imaginary parts of the dispersion correction(f' and f"). Can any one help me by suggesting some database suitable for LS1, which consits the real and imaginary dispersion corrections f