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[zhangtingPKU <zhangting@pku.edu.cn>]

Dear everyone

 

      When I calculating the phonon at Gamma point of CsCl crystal, I found that there are great mismatch between the results from LO-TO swith on & off calculations.

When the LO-TO is off, the three optical mode at Gamma are degenerate, and the frequency is about 102.7 cm-1; While, when the LO-TO is on(using CASTEP code,for I do not know how to switch on LO-TO calculation in ABINIT), the highest phonon at Gamma rises to 170 cm-1.

What does the LO-TO spliting mean? Is it important in real CsCl system? And, how to switch on LO-TO calculation in ABINIT code?

      Thanks!

 

　　　　　　　　　　　　　　zhangtingPKU

　　　　　　　　　　　　　　zhangting@pku.edu.cn

　　　　　　　　　　　　　　　　　2006-05-09