Ayala Regla, Martínez José Manuel, R Pappalardo Rafael, Refson Keith, Sánchez Marcos Enrique
Departamento Química Inorgánica, Universidad de Sevilla , 41012 Seville, Spain.
Royal Holloway University of London , Egham Hill, Egham, Surrey TW20 0EX, United Kingdom.
J Phys Chem A. 2018 Feb 22;122(7):1905-1915. doi: 10.1021/acs.jpca.7b12402. Epub 2018 Feb 12.
Hydrolysis of the Bi(III) aqua ion under a range of solution conditions has been studied by means of ab initio molecular dynamics simulations. While the Bi(III) aqua ion is stable in pure water, there is an increasing degree of hydrolysis with the number of hydroxide anions in the medium. This is accompanied by a monotonic decrease of the total coordination number to an asymptotic value of ∼6, reached under extreme basicity conditions. Comparison of the simulated Bi(III) hydrolyzed species with the experimental species distribution at different degrees of basicity suggests that, at the PBE/DFT level of theory here employed, liquid water shows an overly acidic character. Predictions of theoretical EXAFS and XANES spectra were generated from the AIMD trajectories for different Bi hydrolyzed species, [Bi(HO)(HO)], m = 0-3 and n = 7-2. Comparison with available experimental spectra is presented. Spectral features joined to the degree of hydrolysis and hydration are analyzed.
通过从头算分子动力学模拟研究了一系列溶液条件下Bi(III)水合离子的水解情况。虽然Bi(III)水合离子在纯水中是稳定的，但随着介质中氢氧根阴离子数量的增加，水解程度也在增加。这伴随着总配位数单调下降至在极端碱性条件下达到的约6的渐近值。将模拟的Bi(III)水解物种与不同碱度下的实验物种分布进行比较表明，在此处采用的PBE/DFT理论水平下，液态水表现出过度酸性的特征。从不同Bi水解物种[Bi(HO)(HO)]（m = 0 - 3且n = 7 - 2）的AIMD轨迹生成了理论EXAFS和XANES光谱的预测结果。并与现有的实验光谱进行了比较。分析了与水解和水合程度相关的光谱特征。
