[DFTB-Plus-User] eigvev.out & oversqr.dat
Bálint Aradi
aradi at uni-bremen.de
Thu May 13 07:59:14 CEST 2021
Dear Fengling,
Maybe you just forgot to conjugate the eigenvector on the left hand
side? In the complex case the orthogonality relation reads as
(C_i)^* S_ij C_j = delta_ij
where C_i is the i-th eigenvector (the i-th column of the eigenvector
matrix).
Best regards,
Bálint
On 13.05.21 03:55, 邓凤麟 via DFTB-Plus-User wrote:
> Dear DFTB developers and users,
>
>
> I am a new user of DFTB+. Now, I cannot understand the relation between
> overlap matrix S in oversqr.dat and cofficients C in eigvev.out when I
> do a calculation of Silicon crystal.
>
>
> In DFTB, the formula (C^T)_ij S_jk C_kl=delta_il shoud always be
> satisfied. I do a calculation of H2O molecule and obtain the right
> result delta_il, like the previous discussion
> (https://mailman.zfn.uni-bremen.de/pipermail/dftb-plus-user/2017/002504.html
> <https://mailman.zfn.uni-bremen.de/pipermail/dftb-plus-user/2017/002504.html>).
>
>
>
> However, for the Si crystal, I am puzzled when I calculate (C^T)_ij
> S_jk C_kl at random k point.
>
> For the first k point and first eigen vector,
>
> S=
>
> 1.00855+3.40401e-20im … 0.126487-0.0489968im
> 6.09864e-20-0.0437937im 0.115195-0.0619647im
> 1.73134e-18-0.0437937im 0.115195-0.0619647im
> 1.7415e-18-0.0437937im 0.0258335+0.120866im
> -0.068126+0.357226im 4.68655e-17+0.0437937im
> 0.126487+0.0489968im … 0.0338919-5.55196e-17im
> 0.126487+0.0489968im 0.0338919-5.55586e-17im
> 0.126487+0.0489968im 0.751609-4.18909e-17im
>
>
> C=
>
>
> 0.585064 - 0.000778im
> -0.006024 + 0.041804im
> -0.006024 + 0.041804im
> -0.006024 + 0.041804im
> -0.111193 - 0.574401im
> 0.039879 - 0.013912im
> 0.039879 - 0.013912im
> 0.039879 - 0.013912im
>
>
> C^T=
>
> 0.585064+0.000778im -0.006024-0.041804im … 0.039879+0.013912im
>
>
> I hope I use the data from output files in a right way. The input
> file can be found in attachments.
>
>
> Best regards,
>
> Fenglin Deng
>
>
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--
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b-aradi/
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