Photoemission and reflection in the dynamic scattering of almost parallel x-ray beams

Angular dependences of photoemission and reflection for the case of a small-divergent beam diffracted by strongly asymmetric monochromators are determined and calculated. CuKsub(α) and VKsub(α) radiation have been used. Essential increase of anomalous change of photoemission is disclosed. The effect of small but finite divergence is analyzed. The calculated and experimental results satisfactorily coincide, possible reasons for their difference are discussed. Advisability of using two-crystal and three-crystal schemes for measuring photoemission angular dependences is compared