第一性原理计算研究金属Nb和间隙氢原子的相互作用

First principles investigation of interaction between interstitials H atom and Nb metal

应用第一性原理计算方法,研究了H在金属Nb体心立方晶格中的间隙占位情况,并讨论了占位能和间隙大小的关系.分析了H在间隙位和Nb金属晶格的相互作用,并讨论了相互作用对电子结构的影响.结果表明:除了间隙大小直接影响溶解能的大小之外,H的1s电子和Nb的3d电子有比较强的成键作用,也是导致H在Nb晶格中溶解能较低的一个重要原因.估算了500℃下H在Nb晶格中的扩散系数大约为7.8×10^(-9)m^2/s,和实验结果基本符合.

Understanding of the interaction between Nb and interstitial H is helpful for using Nb metallic membrane as H_2 purification selective membrane.By first-principles calculations,the site occupation of H in the interstitials of the bcc Nb lattice is studied,and the relation between the site energy and the size of the interstitial is discussed.The interaction between interstitial H and Nb lattice is analyzed and the influence of the electronic structure on the interaction is discussed.The results show that in addition to the influence of the interstitial size on the H solution energy,strong bonding interaction between H-ls and Nb-3d is another important reason for the low H solution energy in Nb lattice.The H diffusion coefficient in Nb metal is evaluated and results show that it is approximately 7.8×10^（-9） m^2/s at 500℃,Which is in agreement with experimental observation.