Hazebroucq Sandrine, Picard Gérard S, Adamo Carlo
Laboratoire d'Electrochimie et de Chimie Analytique, Centre National de la Recherche Scientifique Unite Mixte de Recherche 7575, Ecole Nationale Supérieure de Chimie de Paris, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05, France.
J Chem Phys. 2005 Jun 8;122(22):224512. doi: 10.1063/1.1931648.
The solvation of lanthanides [here Gd(III)] in molten LiCl and KCl has been studied using a classical solvation approach, based on clusters of increasing size. In particular, density-functional calculations have been carried out on charged and neutral clusters, containing up to 35 chlorine halide molecules. A number of properties have been then evaluated and analyzed, including structural, vibrational, and thermochemical data. Special attention has also been devoted to the analysis of the local structure of the solvent surrounding the Gd3+ cation, a problem deeply investigated by experimentalists. Our results show that the charged clusters are not suitable to model the first solvation shell in such species, since their structures are strongly affected by the large electrostatic contribution. In contrast, more reliable simulations are obtained using the neutral clusters. In the latter, the coordination of Gd(III) in molten salts is computed to be 8 or 6, according to the salt LiCl or KCl. Furthermore, a good agreement is found with the experimental structural data and Raman spectra. Finally, preliminary results of potential interest for the estimation of solvation thermodynamics, a key parameter for exploiting molten salt chemistry, are reported for neutral clusters.
采用基于尺寸不断增大的团簇的经典溶剂化方法，研究了镧系元素（此处为Gd(III)）在熔融LiCl和KCl中的溶剂化作用。具体而言，对包含多达35个氯化物分子的带电和中性团簇进行了密度泛函计算。随后评估和分析了许多性质，包括结构、振动和热化学数据。还特别关注了围绕Gd3+阳离子的溶剂的局部结构分析，这是实验人员深入研究的一个问题。我们的结果表明，带电团簇不适用于模拟此类物质中的第一溶剂化层，因为它们的结构受到大的静电贡献的强烈影响。相比之下，使用中性团簇可获得更可靠的模拟结果。在后者中，根据盐LiCl或KCl，计算出Gd(III)在熔盐中的配位数为8或6。此外，与实验结构数据和拉曼光谱结果吻合良好。最后，报告了中性团簇在溶剂化热力学估计方面的初步潜在有趣结果，溶剂化热力学是利用熔盐化学的关键参数。
