H_4^+分子离子的电声耦合与声子耦合及其杨-泰勒畸变的群论分析  

Analysis of the Vibronic Coupling and Phonon Coupling and Jahn-Teller Distortion for H_4^+ Molecular Ions Using Group Theory

作　　者：冯胜奇[1] 方海[1] 邱胜桦[1] 刘翠青[1] 

机构地区：[1]韩山师范学院物理与电子工程系,广东潮州521041

出　　处：《信阳师范学院学报（自然科学版）》2013年第1期32-36,共5页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：广东省自然科学基金项目(34613);潮州市科研项目(2012H02);韩山师范学院科研项目(LT201205)

摘　　要：利用群论和量子理论研究了具有D4h对称性构型的H4+分子离子的电声耦合与声子耦合及其杨-泰勒畸变等问题.研究发现,H4+分子存在5种不同的声子态,它们分别具有D4h群下的a1g、b1g、b2g、b2u与eu对称性,其中声子态eu具有红外活性,声子态a1g、b1g、b2g具有拉曼活性,而声子态b2u则是非活性的;在H4+的声子态中只有b1g、b2g是其活跃的声子态;声子态eu与eu之间的耦合将会产生耦合声子态a1g、b1g、b2g;由于电声耦合的缘故,H4+分子离子发生了杨-泰勒畸变,Egb1g与Egb2g系统的杨-泰勒畸变方向是D4h→D2h,而Eg(b1g+b2g)系统的畸变方向则是D4h→C2h,畸变的同时也将导致H4+分子的基态能级发生分裂.The vibronic coupling,phonon coupling and Jahn-Teller distortion for H＋4 molecular ions with the D4h symmetry configuration are studied using group theory and quantum theory in this paper.The study results show： H＋4 molecular ions have five kinds of phonon states,they have the symmetries of a1g、b1g、b2g、b2u and eu under the group D4h.The phonon state eu refers to infrared activity,the phonon states a1g,b1g and b2g refer to Raman activity,and the phonon state b2u is inactive.Among the phonon states of H＋4 molecular ions,only the phonon states b1g and b2g are the active phonon states.The coupling between the phonon state eu and eu should generate the coupling phonon states a1g,b1g and b2g.The Jahn-Teller distortion of systems should occur because of the vibronic coupling of H＋4 molecular ions,the Jahn-Teller distortion directions of the Egb1g and Egb2g systems are D4h→D2h,and the Jahn-Teller distortion direction of the Eg（b1g＋b2g） system is D4h→C2h.At the same time,the Jahn-Teller distortion should cause energy level splitting of H＋4 molecular ions.

关 键 词：H4+分子离子 电声耦合 声子耦合 杨-泰勒畸变 

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