Description:
<jats:title>Abstract</jats:title><jats:p>A dynamical scattering theory is developed in a crystal with distortions of second class. The method of movement separation is used to derive the equations determining the wave field in imperfect crystals. For a perfect crystal the obtained equations have an additional solution corresponding to an oscillation process of the overtone type with a frequency two times larger than the pendellösung one.</jats:p>