Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry, Beijing Institute of Technology, Beijing 100081, PR China.
Chemphyschem. 2013 Jun 24;14(9):1969-76. doi: 10.1002/cphc.201300077. Epub 2013 Apr 29.
The adsorption properties of water molecules on an MgSO4 (100) surface were investigated by using density functional theory (DFT) and supercell models. Optimized stable geometries of one and more than one water molecules adsorbed on an ideal MgSO4 (100) surface were obtained. The configurations with water molecules adsorbed on atoms of the second and third atomic layers of the MgSO4 (100) surface are quite stable. After adsorption, the separations between both the adjacent Mg atoms (R(Mg-Mg)) and the adjacent O atoms of the surface (R(O-O)) increase, which indicates that the MgSO4 (100) surface starts to deliquesce. In addition, water molecules are more likely to adsorb onto a defective surface rather than an ideal surface. Mulliken population analysis suggests that fewer charges transfer to the water molecule from the Mg atom of a defective substrate. Finally, Raman spectra were calculated for 0.5, 1, and 2 ML (ML=monolayer) water adsorbed on an MgSO4 (100) surface, which is helpful for further related experiments.
采用密度泛函理论（DFT）和超晶胞模型研究了水分子在 MgSO4（100）表面的吸附特性。获得了单分子和多于单分子的水分子在理想 MgSO4（100）表面吸附的优化稳定结构。水分子吸附在 MgSO4（100）表面第二层和第三层原子上的结构非常稳定。吸附后，相邻 Mg 原子之间的距离（R（Mg-Mg））和表面相邻 O 原子之间的距离（R（O-O））增大，表明 MgSO4（100）表面开始潮解。此外，水分子更容易吸附在有缺陷的表面而不是理想的表面上。Mulliken 布居分析表明，从缺陷衬底的 Mg 原子向水分子转移的电荷更少。最后，计算了在 MgSO4（100）表面吸附 0.5、1 和 2 ML（ML=单层）水的拉曼光谱，这有助于进一步的相关实验。
