Teaching diffraction with the aid of computer simulations

A high degree of motivation and very effective learning can be achieved by the combination of multimedia presentations with computer simulations of structures and their corresponding Fourier transforms. Computer simulations of structures offer the unique advantage that students see both the structure and the resulting Fourier transform. Furthermore, since any type of structure can be simulated, a systematic approach to diffraction can be taught with maximum efficiency. The students can simulate their own structures, modify these and observe the corresponding changes in reciprocal space. In the course reported here, students are guided through a series of simulations covering diffraction by individual atoms and small aggregates, reciprocal-space geometry, convolution, modification of a structure, the crystallographic phase problem, inverse Fourier transformation, anomalous scattering, powder diffraction and disordered crystals. The course is supplemented by World Wide Web pages that guide self study and prompt the students to try out their own simulations and observe the effect in reciprocal space.