Anomalous dispersion calculations near to and on the long-wavelength side of an absorption edge

Recent experimental measurements have revealed systematic differences between measured values of f' and those calculated by the method of Cromer & Liberman [J. Chem. Phys. (1970), 53, 1891-1898] when the incident X-ray is near to and on the long-wavelength side of an edge. The source of the discrepancy has been identified and some previously published values of f' are corrected. These corrections also apply to Table 2.3.1 in International Tables for X-ray Crystallography, Vol. IV [(1974), Birmingham: Kynoch Press].