A Density Functional Theory Study of the Charge State of Hydrogen in Metal Hydrides
A Density Functional Theory Study of the Charge State of Hydrogen in Metal Hydrides
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DOI：
10.1021/jp911811r
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发表时间：
2010-05
影响因子：
3.7
通讯作者：
S. Aboud;J. Wilcox
中科院分区：
文献类型：
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作者：
S. Aboud;J. Wilcox
采用密度泛函理论和Bader电荷分析方法研究了氢在钒、铌、钽、钯和铌-钯合金中的电荷状态。在不同的浓度和氢位配置范围内，我们发现纯5族金属中氢的净电荷始终在约- 0.51e和- 0.64e之间，而钯中氢的净电荷值明显小得多，为0.3e。虽然有间接证据表明，电子电荷在氢在5族金属中的溶解度和扩散性中起作用，但这是第一次量化电荷值的工作。氢倾向于迁移到金属晶格中使其总电荷密度最小的区域，这通常对应于bcc金属中的t位。研究发现，由于晶格变形，氢在钒的o位上的电荷可能略低，这可能解释了钒氢化物中T位和o位都占据的原因。
Density functional theory and Bader charge analyses were used to investigate the charge state of hydrogen in vanadium, niobium, tantalum, palladium, and niobium−palladium alloys. Over a range of concentrations and hydrogen-site configurations, it is found that hydrogen consistently acquires a net charge of between approximately −0.51e and −0.64e in the pure group 5 metals compared with a significantly smaller value of 0.3e in palladium. Although there is indirect evidence that the electronic charge plays a role in the solubility and diffusivity of hydrogen in the group 5 metals, this is the first work to quantify the value of the charge. Hydrogen tends to migrate to regions of the metal lattice that minimize its overall charge density, which generally corresponds to the T-site in the bcc metals. It is found that the charge of hydrogen at the O-site of vanadium can be slightly lower due to lattice deformation and may explain the occupation of both T- and O-sites in vanadium hydrides.