title: The effect of urea on the morphology of NaCl crystals: A combined theoretical and simulation study.
abstract: It has been known for over a century that the presence of cosolvents such as urea and formamide can alter the morphology of NaCl crystals grown from solution. To help understand this effect we have been developing a theoretical approach based on the Kirkwood-Buff (KB) theory of solutions, and have combined this with computer simulations of the interation of urea with different crystal faces of NaCl. In this way one can predict the effect of urea on the thermodynamic stability of different NaCl faces, with atomic level detail provided by the simulations. We observe that urea is preferentially excluded from 100 and 111 crystal faces, but is less excluded from 111 faces which present chloride ions at the surface. The results indicate that the 111 face is stabilized in urea solutions and promotes the formation of octahedral over cubic NaCl crystals. The approach is totally general and can be applied to understand a variety of interfacial properties. Furthermore, we apply KB theory to study several other issues regarding the simulation of crystal growth.
authors.affiliation: Department of Chemistry, 213 CBC Building, Kansas State University, Manhattan, KS 66506-0401, Tel: 785-532-5109, , pesmith@ksu.edu.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Smith
references.citation: J Am Chem Soc. 2005 Feb 16;127(6):1975-82
references.pmid: 15701033
references.citation: J Phys Chem B. 2006 Feb 16;110(6):2862-8
references.pmid: 16471896
references.citation: J Phys Chem B. 2008 Jul 31;112(30):8975-84
references.pmid: 18610955
references.citation: J Chem Phys. 2004 Aug 1;121(5):2180-6
references.pmid: 15260772
references.citation: J Phys Chem B. 2007 May 17;111(19):5233-42
references.pmid: 17447807
references.citation: Biophys J. 2006 Aug 1;91(3):849-56
references.pmid: 16679363
references.citation: J Chem Phys. 2006 Jan 14;124(2):024513
references.pmid: 16422617
references.citation: Nature. 2005 Nov 3;438(7064):70-3
references.pmid: 16267550
references.citation: J Comput Chem. 2006 Oct;27(13):1477-85
references.pmid: 16823811
references.citation: J Am Chem Soc. 2006 Oct 18;128(41):13568-74
references.pmid: 17031971
references.citation: J Chem Phys. 2006 Apr 21;124(15):154713
references.pmid: 16674257