B_2H_6分子声子态及声子间耦合的群论分析与Mathematica应用  

On Phonon States & couplings for B_2H_6 Molecules by Using Group Theory and Mathematica Application

作　　者：王仙枝[1] 冯胜奇[2] 

机构地区：[1]韩山师范学院数学与信息技术系,广东潮州521041 [2]韩山师范学院物理与电子工程系,广东潮州521041

出　　处：《绵阳师范学院学报》2012年第5期38-42,共5页Journal of Mianyang Teachers＇ College

基　　金：广东省自然科学基金项目(NO.34613)

摘　　要：利用群论和对称性分析的方法研究了具有D3d对称性构型的B2H6分子的声子态及其声子间耦合等问题。研究发现,B2H6存在5种不同的声子态,它们分别具有D3d群下的a1g、a1u、a2u、eg与eu对称性,其中a2u与eu具有红外活性,a1g和eg具有拉曼活性,而a1u是非活性的;在B2H6的声子态中只有eg是活跃的声子态;活跃声子态eg与eg之间的耦合作用将会产生耦合声子态a1g和eg;B2H6分子的电声耦合作用一定会导致B2H6分子发生杨-泰勒畸变,畸变致使B2H6分子从D3d对称性降低到C2h对称性。The symmetries of phonon states and phonon couplings for B2 H6 molecules with D3a symmetry configuration are analyzed by using group theory and the methods of symmetry analyses in this paper. First of all, the symmetries of phonon states for B2H6 molecules are studied, and the infrared and Raman activities of the vibration modes of the molecule are discussed. Then, the vibronic coupling and the active phonon states for B2H6 molecules are analyzed. Finally, the phonon couplings for B2H6 molecules are further studied also by using group theory, and the CG coefficient of the phonon coupling is computed by using Mathematica program. The results show： B2H6 molecules have five kinds of phonon states, they have the symmetries of als ,alu ,a2u,eg and eu under the group D3d. The phonon states a2 and e, refer to infrared activity, the phonon states a1g and eg refer to Raman activity, the phonon state alu is inactive. Among the phonon states of B2H6 molecules, only the phonon state eg is the active phonon state. The coupling between the phonon eg and eg should generate the coupling phonons a1g and eg. The symmetry of B2H6 molecules should be lowered to C2h from D3d because of the vibronic coupling of B2H6 molecules.

关 键 词：B2H6分子 红外活性 拉曼活性 声子耦合 群论 

分 类 号：O561.1[理学—原子与分子物理] O413.1[理学—物理]