Chen Jian-Cheng, Reischl Bernhard, Spijker Peter, Holmberg Nico, Laasonen Kari, Foster Adam S
COMP Centre of Excellence and Department of Applied Physics, Aalto University, FI-00076 Helsinki, Finland.
Phys Chem Chem Phys. 2014 Nov 7;16(41):22545-54. doi: 10.1039/c4cp02375g.
We have used ab initio molecular dynamics (AIMD) simulations to study the interaction of water with the NaCl surface. As expected, we find that water forms several ordered hydration layers, with the first hydration layer having water molecules aligned so that oxygen atoms are on average situated above Na sites. In an attempt to understand the dissolution of NaCl in water, we have then combined AIMD with constrained barrier searches, to calculate the dissolution energetics of Na(+) and Cl(-) ions from terraces, steps, corners and kinks of the (100) surface. We find that the barrier heights show a systematic reduction from the most stable flat terrace sites, through steps to the smallest barriers for corner and kink sites. Generally, the barriers for removal of Na(+) ions are slightly lower than for Cl(-) ions. Finally, we use our calculated barriers in a Kinetic Monte Carlo as a first order model of the dissolution process.
我们利用从头算分子动力学（AIMD）模拟研究了水与氯化钠表面的相互作用。正如预期的那样，我们发现水形成了几个有序的水化层，其中第一层水化层中的水分子排列方式使得氧原子平均位于钠位点上方。为了理解氯化钠在水中的溶解过程，我们随后将AIMD与受限势垒搜索相结合，以计算从（100）表面的平台、台阶、角和扭结处溶解Na(+)和Cl(-)离子的能量学。我们发现，势垒高度呈现出系统的降低趋势，从最稳定的平坦平台位点开始，经过台阶，到角和扭结位点的势垒最小。一般来说，去除Na(+)离子的势垒略低于去除Cl(-)离子的势垒。最后，我们将计算得到的势垒用于动力学蒙特卡罗模拟，作为溶解过程的一阶模型。
