带有碳杂质的钨中氢稳定性的第一性原理研究

Stability of hydrogen in tungsten with carbon impurity:a first-principles study

应用第一性原理计算方法研究了碳(C)原子对钨(W)中氢(H)原子稳定性的影响.本征W中,当C-H间距离为～2.5(?)时,H的溶解能出现最低值,此时为H最稳定的位置.W中存在空位时,由于C的影响,H占据的最佳电子密度面值为0.10(?)^(-3).研究发现,W中单空位最多能容纳10个H原子,且不能形成H分子,不同于没有C存在的情况,表明C对W中H稳定性存在很大影响.此外,当两个C原子存在于空位中时,H占据的最佳电子密度面值变为0.13(?)^(-3).

Stability of hydrogen（H） in tungsten（W） with carbon（C） impurity is investigated by using the first-principles method.In intrinsic W,C exhibits a week attractive interaction with H at a distance of ~2.5A,and it is the most stable site of H in the bulk W with C.In the presence of the monovacancy in W,H prefers to bind onto an isosurface of the same charge density of 0.10 A^（-3）,due to the existence of C.Our research finds that the monovacancy in W can contain only ten H atoms and H molecule cannot be formed in comparison with the result without C,suggesting a strong effect of C on H stability in W.When two C atoms exit in the vacancy,the charge density of the isosurface that H binds onto is 0.13 A^（-3）.