电场作用下MgS分子电子激发特性的理论研究  

Electric Field Effects On Electronic Excited States of MgS

作　　者：谭兴凤[1,2] 蔡雪梅[1] 隆正文[2] 

机构地区：[1]重庆邮电大学光电工程学院,重庆400065 [2]贵州大学理学院,贵州贵阳550025

出　　处：《贵州大学学报（自然科学版）》2011年第3期15-20,共6页Journal of Guizhou University:Natural Sciences

基　　金：国家自然科学基金(10865003)

摘　　要：以6-311++G(2D)为基函数,采用密度泛函的B3LYP方法优化了不同外电场下MgS分子的稳定几何构型,分析了电偶极矩、电荷分布、HOMO能级、LUMO能级、能隙、红外光谱和谐振频率等随电场的变化情况,利用杂化CIS-DFT(B3LYP)方法在相同基组下研究了外电场下MgS分子激发态。计算结果表明:分子结构与外电场有着强烈的依赖关系;除此之外,基态键长和分子偶极矩μ随电场增加而增大;HOMO能级和LUMO能级始终是减小的,而能隙先增大后减小,在电场为0.03 a.u.时,达到最大值2.58650 eV;外电场对MgS分子的激发能、振子强度和振动频率均影响强烈。The density functional theory（DFT） was used to study the equilibrium structure of the ground state,the dipole moment,the charge distribution,the HOMO energy level,the LUMO energy level,energy gaps,the infrared spectrum and the harmonic frequency of MgS molecule at the 6-311＋＋G（2D） basis set under the different external fields.In addition,the excited states at different external electric fields were also investigated using a hybrid method combined with the single-excitation configuration interactions（CIS） with density functional theory（DFT）,i.e.CIS-DFT（B3LYP） at the same basis set.The calculated results show that the molecular geometries are strongly dependent on the field strength.Additionally,the bond length and dipole moment μ of MgS molecule are increased with respect to the external electric field density.However,the HOMO energy level and LUMO energy level are always decreased.The energy gap between the HOMO energy level and LUMO energy level is increased with the electric field at the beginning and then reduced.At F=0.03 a.u.,the maximum of energy gaps is 2.58650 eV.The external electric field has a strong influence on excitation energies,oscillator strengths and harmonic frequency of the MgS.

关 键 词：外电场 结构参数 能隙 理论计算 MgS 

分 类 号：O561.1[理学—原子与分子物理] O561.3[理学—物理]