Authors: Anik Sen Bishwajit Ganguly
Publish Date: 2012/11/09
Volume: 131, Issue: 12, Pages: 1296-
Abstract
The dissolution phenomenon of potassium chloride microcrystal in water has been studied using DFT calculations and molecular dynamics studies DFT study reveals the departure of Cl− to be more pronounced from the edge positions compared to the corner sites of the KCl KCl6H2O n n = 1–15 microcrystal lattice The dissolution initiates through the movement of a Cl− from the edge of the crystal lattice 519 Å at n = 4 water molecules in agreement with the separation of ions from a single KCl molecule This separation is more evident with the cluster of 6 water molecules 612 Å The characteristics of KCl dissolution dynamics such as the sequential departure of ions from the crystal the hydrated ions and the dynamical role of the water molecules are further studied by classical molecular dynamics simulations employing GROMACS force field Molecular dynamics calculations are performed with a larger crystal of KCl with 100 plane consisting of 108 K+ and 108 Cl− ions The MD studies have been extended with relatively unstable planes of KCl 110 consisting of 105 K+ and 105 Cl− ions and 111 consisting of 120 K+ and 120 Cl− ions The simulations revealed that the dissolution of 110 and 111 planes is relatively faster than that of the stable 100 plane A mean square displacement analysis also supported this observation The dissolution of the ions generally occurs from the top layer of 100 surface while other layers remain intact However such a definite pattern of dissolution is not noticed with 110 and 111 planesAuthors thank DST New Delhi India for financial support of this work One of the authors AS is thankful to UGC New Delhi India for awarding senior research fellowship We thank Prof Jim Thomas University of Sheffield UK for helping in preparing the manuscript Authors thank the reviewers for their comments and suggestions that have helped to improve the article
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