crystalXgraphic 2 is a major update demonstrating many features of Bragg diffraction in 2D and 3D Bravais lattices and the common crystal structures of diamond, sodium chloride, cesium chloride, zincblende and hexagonal close packed in a simple-to-use, 3D, real-time, interactive simulation. The simulation uses the fundamental properties of wave interference in 3D to explore qualitatively and semi-quantitatively a very wide range of diffraction phenomena. Crystal lattice spacings and angles, orientation, incident wavelength and many other parameters are adjustable in real-time. Diffraction patterns are generated on either a flat screen (analagous to a photographic plate) or a spherical screen surrounding the crystal that shows Bragg spots in a 360 degree undistorted view. For the flat screen, a 3D plot of the diffraction pattern intensity is presented together with an adjustable 2D section from the 3D plot that allows analysis of the size and separation of diffraction maxima. Using an adjustable cursor on the surface of the spherical screen, the combination of Miller indices appearing in the Bragg plane spacings of the cubic lattices can be immediately read out and Miller indices identified.
The detected diffraction pattern can be integrated over a range of wavelengths in a wavelength scan to show the broadband image of crystal zone reflections on a flat screen.
At small wavelengths, when the wavevector extends far into the reciprocal lattice, the intersection of the large Ewald sphere with the broadened reciprocal lattice points gives rise to High Order Laue Zones (HOLZ), that are seen as bands of circles on the spherical screen.