TEACHING DIFFRACTION PHYSICS BY COMPUTER SIMULATIONS ¹Neder, R.B. & ²Proffen, Th., ¹Institut für Kristallographie und Mineralogie, Universität München, Theresienstr.41, 80333 München, Germany, ²Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia

A high degree of motivation and very effective learning can be achieved by combining multimedia presentations with computer simulations of structures and their corresponding Fourier transform. Computer simulations of structures [1] offer the unique advantage that the students will 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, we guide the students through a series of simulations covering: diffraction by individual atoms and small aggregates, reciprocal space geometry, convolution, modification of a structure, crystallographic phase problem, inverse Fourier transform, anomalous scattering, powder diffraction and disordered crystals. The course is supplemented by WWW pages [2], that guide a self study and prompt the students to try out their own simulations and observe the effect in reciprocal space.

[1] Neder, R.B., (1994): DISCUS, a program to simulate defect structures and diffuse scattering. Z.Kristallogr. Suppl. 7, 744. see: WWW: http://www.kri.physik.uni-muenchen.de /geo/crystal/discus/discus.html

[2]Neder, R.B., (1995): Teaching Guide X-ray Diffraction. see:WWW:http://www.kri.physik.uni-muenchen.de /geo/crystal/teaching/teaching.html