X-ray standing wave as a result of only the imaginary part of the atomic scattering factor

The X-ray standing wave has been studied when the real part of the scatteri ng factor is zero. In the symmetric Laue case, the phase of the standing wa ve advances by pi when the deviation parameter W changes from -1 to 1, whic h is the same variation as in the usual symmetric Bragg case when only the real part of the scattering factor exists. However, the phase in the former case is different from that in the latter by pi/2. By using the standing w aves, the origins of the anomalous transmission and anomalous absorption ef fects reported by Fukamachi & Kawamura [Acta Cryst. (1993), A49, 384-388] h ave been analysed. The standing wave in the Laue case can give rise to a mo re accurate method of site determination of a specified impurity atom as we ll as a wider range of applications than a conventional standing-wave appro ach.