受限于平行硅板中水的分子动力学模拟

Molecular Dynamics Study of Water Molecules Confined in Parallel Si plates

采用分子动力学模拟方法研究了不同间距(16.6,13.6,和11.8A)两硅平板之间水分子的结构性质,模拟结果显示:受限水呈现出与体态水完全不同的结构性质,即水分子的分布依赖于两板间距.间距为16.6A时,硅壁的吸引力造成了其附近形成两个明显的水层,其中的水分子的O-H平行于壁面形成氢键.随着间距的减小,第二层水分子中的O-H键由平行于壁面转向垂直于壁面,与临近的水层通过氢键相连.此外,模拟结果表明,在不同上下板间距情况下,被壁面吸引所形成的水层中水分子的结构取向基本没有变化.

Molecular dynamics simulation is carried out to describe the structure properties of water molecules confined between two Si plates separated by gaps of 16. 6, 13. 6, and 11.8 A. The simulation results indicate that the arrangements of the water molecules are dependent on the gap size, which present great differences from the bulk water. For the largest gap size, two density peaks are formed in the vicinities of both plates because of strong adsorption of the Si surfaces. Most of the O-H bonds within those water layers lie parallel to the plate surface and form a flat hydrogen network. However, the orientations of the O-H bonds in the second water layer parallel to the surface rearrange to form hydrogen bonds between the water layers as the separation between the plates is decreased. Furthemore, the results indicate that the orientation of the first water layer directly absorbed by the plate surface does not change as the gap size between the two Si plates is reduced.