Size-Dependent Phase Stability of a Molecular Nanocrystal: a Proxy for Investigating the Early Stages of Crystallization

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Zahn D, Anwar J
Zeitschrift: Chemistry - A European Journal
Jahr der Veröffentlichung: 2011
Band: 17
Heftnummer: 40
Seitenbereich: 11186-11192
ISSN: 0947-6539
eISSN: 1521-3765


Abstract

We make the link between the size-dependent phase stability of a nanocrystal and the phase-transition behavior of emerging crystallites during the earliest stages of crystallization, by using the former as a proxy for the latter. We outline an extension of the classical nucleation theory to describe crystal nucleation and subsequent transformations of competing polymorphic phases that characterize Ostwald's rule of stages. The theoretical framework reveals that the relative stability of the competing phases is a function of cluster size, which in turn varies with time, and therefore explains the complex transformation behavior observed for some systems. We investigated the stability of a nanocrystal of dl-norleucine by means of molecular simulation as a proxy for post-nucleation phase-transformation behavior in emerging crystallites. The simulations reveal that, for nanocrystals, the surface energy of the transition state of a transformation can dominate the barrier to phase change, thus causing metastable phases to be stabilized, not because they are thermodynamically stable, but rather due to kinetic hindering. Therefore, in the context of the earliest stages of crystal growth, not only does phase stability vary as a function of cluster size, and hence time, but thermodynamically feasible transformations are also prone to kinetic hindering.


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Zahn, Dirk Prof. Dr.
Professur für Theoretische Chemie


Zusätzliche Organisationseinheit(en)
Exzellenz-Cluster Engineering of Advanced Materials


Einrichtungen weiterer Autorinnen und Autoren

University of Bradford


Forschungsbereiche

A3 Multiscale Modeling and Simulation
Exzellenz-Cluster Engineering of Advanced Materials


Zitierweisen

APA:
Zahn, D., & Anwar, J. (2011). Size-Dependent Phase Stability of a Molecular Nanocrystal: a Proxy for Investigating the Early Stages of Crystallization. Chemistry - A European Journal, 17(40), 11186-11192. https://dx.doi.org/10.1002/chem.201100710

MLA:
Zahn, Dirk, and Jamshed Anwar. "Size-Dependent Phase Stability of a Molecular Nanocrystal: a Proxy for Investigating the Early Stages of Crystallization." Chemistry - A European Journal 17.40 (2011): 11186-11192.

BibTeX: 

Zuletzt aktualisiert 2019-16-03 um 05:08