Ab Initio Studies of Calcium Carbonate Hydration

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• 作者：Josue A. Lopez-Berganza ; Yijue Diao ; Sudhakar Pamidighantam ; Rosa M. Espinosa-Marzal
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：119
• 期：47
• 页码：11591-11600
• 全文大小：498K
• ISSN：1520-5215

文摘

Ab initio simulations of large hydrated calcium carbonate clusters are challenging due to the existence of multiple local energy minima. Extensive conformational searches around hydrated calcium carbonate clusters (CaCO₃路nH₂O for n = 1鈥?8) were performed to find low-energy hydration structures using an efficient combination of Monte Carlo searches, density-functional tight binding (DFTB+) method, and density-functional theory (DFT) at the B3LYP level, or M酶ller鈥揚lesset perturbation theory at the MP2 level. This multilevel optimization yields several low-energy structures for hydrated calcium carbonate. Structural and energetics analysis of the hydration of these clusters revealed a first hydration shell composed of 12 water molecules. Bond-length and charge densities were also determined for different cluster sizes. The solvation of calcium carbonate in bulk water was investigated by placing the explicitly solvated CaCO₃路nH₂O clusters in a polarizable continuum model (PCM). The findings of this study provide new insights into the energetics and structure of hydrated calcium carbonate and contribute to the understanding of mechanisms where calcium carbonate formation or dissolution is of relevance.