Free energy barriers for homogeneous crystal nucleation in a eutectic system of binary hard spheres

Ganagalla, Srinivasa Rao and Punnathanam, Sudeep N (2013) Free energy barriers for homogeneous crystal nucleation in a eutectic system of binary hard spheres. In: Journal of Chemical Physics, 138 (17). 174503_1-174503_8.

PDF Jou_Chem_Phy_138-17_174503_2013.pdf - Published Version Restricted to Registered users only Download (1MB) | Request a copy

Abstract

In this study, the free energy barriers for homogeneous crystal nucleation in a system that exhibits a eutectic point are computed using Monte Carlo simulations. The system studied is a binary hard sphere mixture with a diameter ratio of 0.85 between the smaller and larger hard spheres. The simulations of crystal nucleation are performed for the entire range of fluid compositions. The free energy barrier is found to be the highest near the eutectic point and is nearly five times that for the pure fluid, which slows down the nucleation rate by a factor of 10(-31). These free energy barriers are some of highest ever computed using simulations. For most of the conditions studied, the composition of the critical nucleus corresponds to either one of the two thermodynamically stable solid phases. However, near the eutectic point, the nucleation barrier is lowest for the formation of the metastable random hexagonal closed packed (rhcp) solid phase with composition lying in the two-phase region of the phase diagram. The fluid to solid phase transition is hypothesized to proceed via formation of a metastable rhcp phase followed by a phase separation into respective stable fcc solid phases.

Item Type:	Journal Article
Publication:	Journal of Chemical Physics
Publisher:	American Institute of Physics
Additional Information:	Copyright of this article belongs to American Institute of Physics.
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	11 Jul 2013 06:28
Last Modified:	11 Jul 2013 06:28
URI:	http://eprints.iisc.ac.in/id/eprint/46822

Actions (login required)

View Item