中文摘要：

采用密度泛函理论,研究了聚变堆第一壁材料中的BeO分子在外电场中的结构,本文选用了B3LYP/6-311g方法优化,研究了外电场（-0.05~0.05a.u.）对BeO分子基态键长、能量、电荷分布、HOMO能级、LUMO能级、能隙及谐振频率的影响.结果表明,电场从-0.05a.u.变化到0.05a.u.时,BeO的能量随正向电场增加而降低,但HOMO能级、LUMO能级以及能隙均随着电场的增加而增大.能隙的增大表明在外电场作用下,BeO分子占据轨道中的电子激发到空轨道更难,在外电场中BeO分子的结构仍然比较稳定.所以,BeO分子可以作为ITER第一壁较好的侯选材料.

英文摘要：

Based on the density functional theory DFT/B3lyp at 6-311g level,the ground states of BeO molecule are optimized.The effects of electric field on the bond length,system energy,charge distribution,energy levels,HOMO-LUMO gaps and the infrared spectrum of BeO molecule have been studied.The results indicate that the system energies decrease as the external electric field from-0.05 to 0.05au.At the same time,the energy gaps between the HOMO and LUMO become separate with increasing electric field.It shows that the structure of BeO molecule is steady under external electric field.Hence,BeO is an ideal material of the first wall in a fusion reactor.