Simulation of the crystal-to-amorphous transformation in irradiated quartz

This paper reports on quartz and other crystalline polymorphs of silica that transform from the crystalline to an aperiodic state under irradiation. There is a need to understand the structural changes involved during this amorphization process. The authors have built an engineering model which simulates the growth of amorphous regions within a crystalline matrix during the crystal-to-amorphous transition in irradiated quartz. The resulting crystal structure is displayed on the computer screen or plotted on a printer with the orthogonal coordinates of all the atoms in the cluster and the interatomic distances stored in a file. The authors find the bond lengths increase by about 3%, which is a reasonable value to expect since quartz expands 14% by volume during the amorphization. The results also show the crystal structure surrounding the strained region to be somewhat disturbed, consistent with what is observed experimentally