How to calculate the BZ Q-points

Deals with issues related to computation of optical spectra in reciprocal space: RPA, TDDFT, local field effects.

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chinaye
Posts: 16
Joined: Wed Mar 25, 2009 9:35 am

How to calculate the BZ Q-points

Post by chinaye » Sun Apr 19, 2009 6:57 am

Hello everyone,
The dimension of the BS kernel is in principle the product of Nv*Nc*K. However, I found in yambo the BSK dimension is equal to Nv*Nc*(BZ Q-points). We are not clear how to determine the quantity "BZ Q-points". Can someone give me some instructions? Thank you very much.
Jianfei Ye, PHD
Shanghai Institute of Ceramic Chinese Academy of Science (SICCAS)
Email:jianfeiye@mail.sic.ac.cn

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andrea marini
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Re: How to calculate the BZ Q-points

Post by andrea marini » Sun Apr 19, 2009 10:43 am

chinaye wrote: The dimension of the BS kernel is in principle the product of Nv*Nc*K. However, I found in yambo the BSK dimension is equal to Nv*Nc*(BZ Q-points). We are not clear how to determine the quantity "BZ Q-points". Can someone give me some instructions? Thank you very much.
Dear Jianfei Ye, the dimension of the BS kernel is indeed given by Nv*Nc*K, where K is the number of K-points in the BZ. In some special case the "BZ Q-points", that is the number of transferred momenta in the whole BZ is equal to K. But how did you reach the conclusion that in Yambo the dimension of the BS kernel is linked to the number of Q-points instead of the number of K-points ? Post some details of your run that we can discuss together.

Cheers

Andrea
Andrea MARINI
Istituto di Struttura della Materia, CNR, (Italy)

chinaye
Posts: 16
Joined: Wed Mar 25, 2009 9:35 am

Re: How to calculate the BZ Q-points

Post by chinaye » Mon Apr 20, 2009 1:32 am

Dear Andrea Marini,
Yes, you are right. The number of BZ K-points is equal to that of BZ Q-points. Thank you very much for your reply.
Jianfei Ye, PHD
Shanghai Institute of Ceramic Chinese Academy of Science (SICCAS)
Email:jianfeiye@mail.sic.ac.cn

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