2020 journal article

Transition Zone Theory Compared to Standard Models: Reexamining the Theory of Crystal Growth from Melts

JOURNAL OF PHYSICAL CHEMISTRY C, 124(34), 18724–18740.

By: J. Martin n, B. Hillis n & F. Hou n

co-author countries: United States of America 🇺🇸
Source: Web Of Science
Added: September 21, 2020

Ideas proposed at the beginning of the 20th century to describe the temperature dependence of crystal growth rates have become accepted as the “standard model.” Specifically, it was proposed that rates are controlled by a thermodynamic driving force, liquid/solid interfacial surface energy requires crystal growth to occur at step or kink sites, and particle diffusion/viscous relaxation also controls the rate of growth. However, as described in this article, these underlying assumptions are inconsistent with the fact that crystal growth from supercooled melts is microscopically irreversible, and the well-known fact that short- and intermediate-range order in melts and crystals is essentially equivalent, precluding the existence of sharp interfaces and the need for material diffusion. By contrast, we recently introduced the Transition Zone Theory of crystallization, TZTc, a condensed matter analogue of Eyring’s transition state theory that uses Kauzmann’s conception of configurational entropy and Adam and Gibbs’ ideas of cooperativity to describe the ensemble characteristics governing crystal growth rates. Here, the TZTc model is applied to the same sets of inorganic oxides and organic molecules that were used to evaluate the apparent decoupling of viscosity from the standard model, as well as to several other materials. Without exception, the TZTc model provides a superior fit to temperature-dependent crystal growth-rate data. With a single model accurately describing diverse crystallizing systems, the three parameters extracted from TZTc, for the first time, provide a platform with which to compare and contrast chemical/physical factors that influence crystallization reactions.