Pu_4^+在D_(4h)结构下的红外-拉曼活性及电声耦合的群论分析

The Group Analysis of Pu_4^+'s Infrared-Ramam Activity and the Election-Phonon Coupling under D_(4h) Structure

利用群论方法分析了Pu4+在D4h结构下振动模式,以及红外-拉曼活性,并且讨论了在以f轨道为基函数下可能存在的电声耦合及其杨-泰勒效应.结果表明,可能发生的杨-泰勒效应系统是Eub1g系统,或者Eub2g系统,或者Eu(b1g+b2g)系统.Eub1g畸变导致Pu4+分子从D4h的正方形结构降低到D2h对称性的菱形D2h结构,Eub2g畸变导致体系变化到矩形的D2h结构.这两种变化导致电子态从Eu分裂为B2u+B3u2个电子态.Eu(b1g+b2g)畸变导致体系变化到菱形的C2h结构,而电子态则分裂为2个Bu电子态.

The Pu4^＋＇s vibration mode and the infrared-Ramam activity have been studied with group analysis under theD4h configuration. The election-phonon coupling and some possible Jahn-Teller effect under the f basis function also have been researched. It is found that the possible Jahn-Teller systems are Eu b1g, or Eu b2g, or Eu b1g ＋b2g）. The E b1g will distort the square geometry of Pu4^＋ （D4h） towards a rhomboid geometry of Dzh ; the Eu b2g will distort the square gometry of Pu4^＋ （D4h） towards a rectangle geometry of D2h ; the above two Jahn-Teller distortions can lead the electronic state Eu to B2u ＋ B3u. The Eu b1g＋b2g） will distort the square gometry of Pu4^＋ （D4h） towards a rhomboid geometry of C2h, and let the electronic state from Eu to 2B,.