Strange results for non-linear suscepbility

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Zhang Xiaole
Posts: 46
Joined: Thu Sep 15, 2011 7:13 am

Strange results for non-linear suscepbility

Post by Zhang Xiaole » Mon Dec 05, 2011 2:16 pm

Dear all,
It's me again,:)
i just have finished the static non-linear suscepblity calculation for KBe2BO3F2 (KBBF), whose space group is 155(R32),every thing goes well (ecut,kpoints testing , structure optimaztion,response calculation),after running anaddb,i obtained the non-linear suscepbility. The results i got is d21=-d22=-d15 are non-zero term which should belong to the point group R3m, and the R32 point group which
i calculate shoud have only non-zero term d11.
i aslo check the log file, according to the parameter acell and rprim the code really determine the space group 155 which is also point group R32.
i am really confused that.
could be some problem in my calculation?
Thanks in advance.

Xiaole
Phd student
Phys Department
Shanghai JiaoTong university, Shanghai, China

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sponce
Posts: 60
Joined: Sat Apr 16, 2011 9:44 am

Re: Strange results for non-linear suscepbility

Post by sponce » Mon Dec 05, 2011 2:24 pm

Dear Xiaole,

Could you gives us the value you are talking about? If the values are small it could be due to numerical accuracy problems. Did you impose a sum rules in your calculation?

Zhang Xiaole
Posts: 46
Joined: Thu Sep 15, 2011 7:13 am

Re: Strange results for non-linear suscepbility

Post by Zhang Xiaole » Mon Dec 05, 2011 2:47 pm

sponce wrote:Dear Xiaole,

Could you gives us the value you are talking about? If the values are small it could be due to numerical accuracy problems. Did you impose a sum rules in your calculation?

Dear sponce
the value is about 0.7pm/V ,it seem like not a numercal problem. i am sorry i couldn't upload my input files right now,and what do you mean by impose sum rules( which parameter control this
process?), i will check later.
by the way,earlier i can visit abinit web site in my lab, but i dont known since when i cant visit it anymore.So every time i have to transmit my files to a U-disk and upload to the forum in my computer at dormitory.



Xiaole
Phd student
Phys Department
Shanghai JiaoTong university, Shanghai, China

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