Crystal Structure Dynamics: Evidence by Diffraction and Spectroscopy

Bragg diffraction is a major tool to solve and refine crystal structures, though it is limited as results obtained from the bulk sample are averaged in time and space. In contrast, spectroscopy is site sensitive, and thus a probe for local structure with high time and space resolution. Combination of both methods may reveal important additional information on crystal structures such as disorder and dynamics, and may even help avoid pitfalls in structure solution. Among the given examples are three minerals, i.e., lawsonite, hemimorphite, leonite, which show phase transitions from dynamically disordered to ordered structures. Continuous evolution from order to dynamic disorder, however without a phase transition, is found in washing soda. Finally, examples of proton dynamics in a tetragonal garnet and in minerals with very strong hydrogen bonds are presented.