B_2H_6分子在C_(2v)势阱中的频率分解及其各向异性效应  

The phonon splitting and anisotropic effect of B_2H_6 molecules in the C_(2v) minima

作　　者：冯胜奇[1] 王仙枝[2] 方海[1] 

机构地区：[1]韩山师范学院物理与电子工程系,潮州521041 [2]韩山师范学院计算机应用与技术系,潮州521041

出　　处：《原子与分子物理学报》2012年第5期770-776,共7页Journal of Atomic and Molecular Physics

基　　金：广东省自然科学基金(34613)

摘　　要：依据杨-泰勒效应理论、量子理论和群论探讨了具有D_(3h)对称性构型的B2Hs分子的E(?)e′系统在C_(2v)势阱中的频率分解及其各向异性现象.借助么正平移变换和标度变换计算出了杨-泰勒畸变后的系统振动频率,结果表明,畸变导致系统二重简并的振动模式e′的振动频率发生了分解,对于系统的4个C_(2v)势阱而言,无论系统处在哪一个势阱中,畸变所导致的频率分解都是相同的;畸变同时还导致系统的振动基态能量比畸变前降低了.正是这种基态能量的降低,使得畸变后系统就达到了一个更加稳定的状态.文中利用群论进一步探讨了系统的频率分解,结果发现,畸变导致系统的二重简并振动态e′分解为两种非简并的振动态,它们分别具有C_(2v)群下的a_1与b_2对称性.系统的频率分解与基态能量的降低就意味着系统的各向同性遭到破坏而呈现出各向异性.Based on Jahn-Teller effect theory, quantum theory and group theory, the phonon splitting and anisotropic phenomena of the E e′ system for B2H6 molecules with D3h symmetry are studied in the C2v minima. The vibration frequency of the system after Jahn-Teller distortion is calculated using the unitary shift transformation and modified scale transformation, it is found that the doubly degenerate vibration state e′ is split into two states and its degeneration is completely lifted because of Jahn-Teller distortion. No matter which of the four C2v minima the system is in, the phonon splitting of the system is completely same. The Jahn-Teller distortion results in that the ground state of the system has lower energy after the distortion than before the distortion, B2H6 molecules will achieve a more stable state after the distortion just for the energy lessening. The phonon splitting is further discussed using group theory in this paper, the discussed results show that the vibration state e′ of the system is split into two states respectively with a1 and b2 symmetries under the group C2v. The phonon splitting signifies that the isotropy of B2H6 molecules is destroyed and its anisotropy should appear.

关 键 词：杨-泰勒畸变 标度变换 频率分解 各向异性 

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