Water clusters confined in icosahedral fullerene cavities

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• 作者：J. Herná ; ndez-Rojas ; ^{jhrojas@ull.es} ; V. Monteseguro ; J. Bretó ; n ^{jbreton@ull.es} ; J.M. Gomez Llorente ^{jmgomez@ull.es}
• 关键词：Water clusters ; Global optimization ; Icosahedral fullerenes
• 刊名：Chemical Physics
• 出版年：2012
• 期刊代码：18_03010104
• 类别：ch
• 出版时间：3 May, 2012
• 卷：399
• 期：Complete
• 页码：240-244
• 文件大小：720 K

摘要

Likely candidates for the global energy minima of endohedral (H₂O)_N@C₆₀ and (H₂O)_N@C₁₈₀, and exohedral (H₂O)_NC₁₈₀ water-fullerene clusters with N 猢?#xA0;20, are found using basin-hopping global optimization. The potential energy surfaces are constructed using both the rigid TIP4P and the flexible q-TIP4P/F potentials to model the water-water interaction, together with a Lennard-Jones potential for the water-fullerene interaction. In agreement with previous ab initio studies, we find that the small C₆₀ cavity is able to encapsulate exothermically only one water molecule. On the other hand, the larger C₁₈₀ cavity can encapsulate up to 17 water molecules exothermically. This threshold value is higher than that reported in a previous ab initio study (N 猢?#xA0;12). New confined water cluster structures are found. One which is particularly interesting is the structure of (H₂O)₁₄@C₁₈₀, with the water molecules forming an internal cage in which six oxygen atoms are located at the vertices of an almost regular octahedron and the eight remaining ones lie on top of the octahedron faces. For N 猢?#xA0;15 one water molecule is always present at the center of the water cage, which is distorted to accommodate the extra molecules.