Determination of the enantiomorph from intensity measurements of three-beam Bragg-surface diffraction of X-rays

An analytical expression for the intrinsic peak width of three-beam Bragg diffraction involving a surface reflection is derived on the basis of the dynamical theory of X-ray diffraction. Utilization of this expression in peak intensity measurements is proved to lead to direct determination of the enantiomorph of the triplet structure-factor invariant involved in a three-beam Bragg-surface diffraction. Effects of polarization on the kinematical peak intensity and on the intrinsic peak width are also discussed.