C42+分子:T2t2系统的杨-泰勒畸变与各向异性现象的群论分析

Analysis on the Jahn-Teller Distortion and Anisotropic Phenomena of the T2t2 System for C42+ Molecu

摘要: 依据群论与量子理论研究了C24+分子的T2t2系统的杨-泰勒畸变与各向异性现象.研究表明,C24+分子的电子基态具有Td群下的E、T1或者T2对称性,C24+分子一共存在3种不同的声子态a1、e与t2,其中只有e、t2是C24+分子的活跃声子态.借助投影算符导出了t2-t2声子耦合中的耦合声子态e的CG系数计算公式,并由此求出了CG系数值.进一步的研究发现:系统的杨-泰勒畸变导致C24+分子从Td对称性降低到C3v对称性;畸变致使C24+分子的三重简并的电子基态能级T2发生分裂;畸变同时还导致C24+分子的振动频率发生分解,而频率的分解就意味着C24+分子在空间上的各向同性遭到破坏而呈现出各向异性.

Abstract: Jahn-Teller distortion and anisotropic phenomena of the T2t2 system for C2+4 molecules were studied based on group theory and quantum theory.It was found that the ground electronic states of C2+4 molecules is E or T1 or T2 under the group Td,the phonon states of C2+4 molecules are a1 and e and t2,only the phonon states e and t2 are the active phonon states of the system.The CG coefficient formulas of the coupling among phonon states t2 were derived using the projection operators,and these CG co...