外电场作用下SF_6分子结构与红外光谱  

Molecular structure and infrared spectrum for SF_6 under external electric fields

作　　者：吴学科[1,2] 唐延林[3] 方世诚 林艳[3] 

机构地区：[1]贵州大学大数据与信息工程学院,贵阳550025 [2]凯里学院物理与电子工程学院,凯里556011 [3]贵州大学理学院物理系,贵阳550025

出　　处：《原子与分子物理学报》2016年第3期385-391,共7页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(11164004);贵州省工业攻关项目(黔科合GY字[2012]3060)

摘　　要：采用密度泛函LSDA方法,在6-311++g(3df,3pd)基组水平上研究了不同外电场下SF_6分子的几何结构、偶极矩、能级分布和红外光谱的变化规律,并利用杂化CIS方法研究了SF_6分子的前9个激发态的激发能、波长和振子强度随外电场的变化情况.结果表明:X轴向上的1S-6F键长受到外场影响最大,随着外电场的增加可能最先趋于断裂;偶极矩随外场的增加而增大,分子总能量随外场的增加而减小;LUMO能级较HOMO能级受外电场影响大,能隙随外场增大而减小;红外光谱吸收峰随外场增大而分开,同时部分原本不具有红外活性的振动模式变成了具有一定的红外活性;激发波长、振子强度、激发能也受外电场影响,但随电场变化比较复杂.The LSDA method of density functional theory at 6 -311 ＋ ＋ g（3df, 3pd） level is used to study the geometrical parameters, dipole moments, energy levels and infrared spectra of the ground state of SF6 molecule under different external electric fields in this paper. On the basis of this, the single - excitation configuration interaction （CIS） is used to study the influences of external electric field on the excited energies, excited wavelengths and oscillators of the first nine excited states. The results show that the bond lengths （1S-6F） will be the greatest impact by X axial electric field, and with the continue increase of electric field, it may be the first to break. The total energy gradually decreases, but the dipole moment increases with increase of the external field. The LUMO energy levels are greatly influenced by external electric fields, but the HOMO energy levels are less affected by the external electric fields. The absorption peaks of infrared spectrum are separated when the external electric field is increased, and part of the vibration modes without infrared activity become to have some infrared activity. The excited energies, excited wavelengths and oscillators are influenced by electric fields, but their changes with the electric fields are relatively complex.

关 键 词：SF6 激发态 外电场 红外光谱 

分 类 号：O561[理学—原子与分子物理] O433[理学—物理]