水溶液
化学
溶剂化壳
分子动力学
水模型
分子
离子
非弹性中子散射
径向分布函数
中子散射
热力学
计算化学
中子
溶剂化
物理化学
物理
量子力学
有机化学
作者
Tatiana M. C. Faro,Gilmar Patrocínio Thim,Munir S. Skaf
摘要
We developed a simple pair-additive Lennard-Jones plus Coulomb potential for molecular simulations of the trivalent cation Al3+ in water which accounts reasonably well for the behavior of aluminum aqueous solutions. The model predicts an octahedral first hydration shell containing 6 water molecules and a trigonal second shell with 12 molecules on average, in good agreement with the available experimentally determined structure. The peak positions of the cation-oxygen radial distribution function are only slightly compressed compared to the x-ray structure, the hydration enthalpy is 10% too low, and the cation self-diffusion coefficient and the single-particle second rank reorientational time are in excellent agreement with inelastic neutron scattering and NMR spectroscopy data, respectively. The model also captures the essential vibrational features of the hydrated [Al(H2O)6]3+ complex. It predicts the main O–Al–O bending mode frequency to within ∼5%, but significantly overestimates the frequency of the totally symmetric Al–O stretching mode. Overall, the accuracy of the proposed model is as good as the best available classical potentials, if not better in some aspects, with a much simpler functional form, which makes it an attractive alternative for computer simulations of Al3+ in more complex aqueous and biomolecular systems.
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