Animation of Crystal Structure Variations with Pressure, Temperature and Composition

Abstract

The mineralogical literature is full of images of crystal structures. These images provide a satisfying way to understand and interpret the results of a crystal structure analysis. They also provide a visual model for understanding many physical properties. For instance, an atomic-scale understanding of the cleavage in mica is immediately obtained once an image of its structure has been seen. Now, however, with the advent of personal computers that can compute and display images quickly, it is possible to routinely create dynamic images of crystal structures, not only by simply spinning them about an axis, but also as a function of temperature, pressure and composition. Examples of these animations are found on the cover of this volume and at the edges of the pages of this chapter. Such dynamic images are effective means for presenting papers at meetings using computer projectors, and could have a place in on-line journals. They can be a useful guide for understanding the results of an experiment and are indispensable in the classroom situation. Constructing a series of images, stored as bitmaps, and then displaying these images one after another is an effective way to make the computer animations. This paper presents an outline of the procedures for making these sorts of movies. It is anticipated that the contents of this chapter will soon be outdated, because computer-generated animation techniques are still rapidly developing. As such, we at least hope to provide a starting point and some motivation for those who would like to present and visualize their data in a new and exciting way. A movie can be easily constructed from a set of data if the data can be characterized by a one-dimensional parameter. Because a movie is a set of images, or frames, displayed as a function of time, we can use …