Molecular Dynamics Simulation Study of the Influence of Cluster Geometry on Formation of C60 Fullerene Clusters in Aqueous Solution
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- 作者：Hojin Kim ; Dmitry Bedrov ; Grant D. Smith
- 刊名：Journal of Chemical Theory and Computation
- 出版年：2008
- 出版时间：February 2008
- 年：2008
- 卷：4
- 期：2
- 页码：335 - 340
- 全文大小：131K
- 年卷期：v.4,no.2(February 2008)
- ISSN：1549-9626
文摘
We have performed atomistic molecular dynamics simulations of linear (1-dimensional), planar (2-dimensional), and icosahedral (3-dimensional) clusters of C60 fullerenesin aqueous solution in order to investigate the influence of cluster geometry on their free energyof formation. As was found in our previous study of the potential of mean force (PMF) as afunction of separation for a single pair of fullerenes in aqueous solution, the interaction betweenfullerenes for all cluster geometries was dominated by direct fullerene-fullerene interactionsand not by water-induced hydrophobic interactions. A coarse-grained implicit solvent (CGIS)potential, given by the PMF for the fullerene pair in water obtained from atomistic simulations,was found to describe well the free energy of formation of the linear cluster, indicating thatmany-body effects, i.e., the influence of neighboring fullerenes on the water-induced interactionbetween a fullerene pair, are negligible for the 1-dimensional geometry. For the 2-dimensionaland particularly the 3-dimensional geometry, however, many-body effects were found to stronglyinfluence hydration, leading to complete dehydration of the central fullerene at close fullerene-fullerene separations for the icosahedral cluster. This strong influence of geometry on hydrationtranslates into water-induced interactions that, while remaining repulsive, as is found for thefullerene pair, are not well described by the two-body CGIS potential obtained from the isolatedfullerene pair, particularly for the 3-dimensional geometry.