Dynamical calculation of crystal truncation rods for surfaces and interfaces using a Cartesian coordinate transformation technique

A dynamical calculation scheme that employs Cartesian coordinates with a z axis normal to the crystal surface to define polarization unit vectors and wavefields is applied to interpret the intensity distribution of crystal tr uncation rods for surfaces and interfaces. A comparison between this calcul ation scheme and the asymptotic iteration approach using the conventional p resentation of the polarization components of the wavefields, with the sigm a and pi components perpendicular to the wavevectors, is presented. It is f ound that the use of Cartesian coordinate systems can provide correct bound ary conditions in determining the wavefield amplitudes, thus leading to a r igorous and general calculation scheme for dynamical diffraction from surfa ces and interfaces.