To extend rational materials design and discovery into the space ofmetastable polymorphs, rapid and reliable assessment of their lifetimes isessential. Motivated by the early work of Buerger (1951), here we investigatethe routes to predict kinetics of polymorphic transformations using solelycrystallographic arguments. As part of this investigation we developed ageneral algorithm to map crystal structures onto each other and constructtransformation pathways between them. The developed algorithm reproducesreliably known transformation pathways and reveals the critical role that thedissociation of chemical bonds along the pathway plays in choosing the best(low-energy barrier) mapping. By utilizing our structure-mapping algorithm wewere able to quantitatively demonstrate the intuitive expectation that theminimal dissociation of chemical bonds along the pathway, or in ionic systems,the condition of coordination of atoms along the pathway not decreasing belowthe coordination in the end compounds, represents the requirement for fasttransformation kinetics. We also demonstrate the effectiveness of thestructure-mapping algorithm in combination with the coordination analysis instudying transformations between polymorphs for which a detailed atomic-levelpicture is presently elusive.
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