Molecular-dynamics simulations of urea nucleation from aqueous solution.
- Salvalaglio M Institute of Process Engineering, Eidgenössische Technische Hochschule Zurich, CH-8092 Zurich, Switzerland; Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland; and.
- Perego C Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland; and Department of Chemistry and Applied Biosciences, Eidgenössiche Technische Hochschule Zurich, CH-8092 Zurich, Switzerland.
- Giberti F Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland; and Department of Chemistry and Applied Biosciences, Eidgenössiche Technische Hochschule Zurich, CH-8092 Zurich, Switzerland.
- Mazzotti M Institute of Process Engineering, Eidgenössische Technische Hochschule Zurich, CH-8092 Zurich, Switzerland;
- Parrinello M Facoltà di informatica, Istituto di Scienze Computazionali, Università della Svizzera Italiana, CH-6900 Lugano, Switzerland; and Department of Chemistry and Applied Biosciences, Eidgenössiche Technische Hochschule Zurich, CH-8092 Zurich, Switzerland parrinello@phys.chem.ethz.ch.
- 2014-12-11
Published in:
- Proceedings of the National Academy of Sciences of the United States of America. - 2015
enhanced sampling
molecular dynamics
nucleation
solution
well-tempered metadynamics
Crystallization
Molecular Dynamics Simulation
Solutions
Thermodynamics
Urea
English
Despite its ubiquitous character and relevance in many branches of science and engineering, nucleation from solution remains elusive. In this framework, molecular simulations represent a powerful tool to provide insight into nucleation at the molecular scale. In this work, we combine theory and molecular simulations to describe urea nucleation from aqueous solution. Taking advantage of well-tempered metadynamics, we compute the free-energy change associated to the phase transition. We find that such a free-energy profile is characterized by significant finite-size effects that can, however, be accounted for. The description of the nucleation process emerging from our analysis differs from classical nucleation theory. Nucleation of crystal-like clusters is in fact preceded by large concentration fluctuations, indicating a predominant two-step process, whereby embryonic crystal nuclei emerge from dense, disordered urea clusters. Furthermore, in the early stages of nucleation, two different polymorphs are seen to compete.
- Language
-
- English
- Open access status
- bronze
- Identifiers
-
- DOI 10.1073/pnas.1421192111
- PMID 25492932
- Persistent URL
- https://folia.unifr.ch/global/documents/293445
Statistics
Document views: 46
File downloads:
- Full-text: 0