k sampling

[Elaheh Akhoundi]

Hi all,

I am trying to understand what it means that k sampling is not implemented for hybrid functionals. Does it mean that the structure is still treated periodically with gamma point or it means  that it is assumed to be a closed system without k points taking into the account. I am confused because when I print out the Kohn Sham Hamiltonian, there is only one block and it seems like there is no list of neighboring cells. 

I would greatly appreciate your help.

Many thanks, 

Elaheh

[hut...@chem.uzh.ch]

Hi

hybrid functionals can only be used in periodic calculations using
the Gamma point only. In this case all operator matrices are
over periodic Gaussian functions.

regards

Juerg Hutter
--------------------------------------------------------------
Juerg Hutter Phone : ++41 44 635 4491
Institut für Chemie C FAX : ++41 44 635 6838
Universität Zürich E-mail: hut...@chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

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To: "cp2k" <cp...@googlegroups.com>
From: "Elaheh Akhoundi"
Sent by: cp...@googlegroups.com
Date: 01/04/2021 02:03PM
Subject: [CP2K:14468] k sampling

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[Elaheh Akhoundi]

Thank you very much for your reply,

I am planning to do transport simulations using the KS Hamiltonian with hybrid functionals. but the Hamiltonian that is printed (using  &AO_MATRICES%%KOHN_SHAM_MATRIX .TRUE.) doesn't have different blocks for neighboring cells. It is probably attributed to the fact that K point keys aren't used with hybrids, even though gamma point is considered in the simulations. If I do hybrid simulations with k point scheme of "GAMMA" I get an error. Is there any way to get the different blocks of Hamitonian (corresponding to neighboring cells) similar to what I can get with PBEs?

Many thanks,

Elaheh 

[hut...@chem.uzh.ch]

Hi

HFX calculations use a special scheme for the Gamma point. The
integrals are summed up early and no operator matrices between
cells is constructed.
The k-point code (even if you only use the Gamma point) has no
HFX part. So you cannot get these matrices from CP2K, it is not
implemented.

regards

Juerg Hutter
--------------------------------------------------------------
Juerg Hutter Phone : ++41 44 635 4491
Institut für Chemie C FAX : ++41 44 635 6838
Universität Zürich E-mail: hut...@chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp...@googlegroups.com wrote: -----
To: "cp2k" <cp...@googlegroups.com>
From: "Elaheh Akhoundi"
Sent by: cp...@googlegroups.com

Date: 01/05/2021 11:17AM
Subject: Re: [CP2K:14478] k sampling

To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/ed55eb7b-277d-4453-92c5-0ee4adb2f9e8n%40googlegroups.com.

[Elaheh Akhoundi]

Thank you very much, It helped me clear up a lot of confusion.

One last question, so It would be pointless for me to go through the source code and try to print raw Hamiltonians myself?

Kind regards,
Elaheh

[hut...@chem.uzh.ch]

> Thank you very much, It helped me clear up a lot of confusion.
> One last question, so It would be pointless for me to go through the source code and try to print raw Hamiltonians myself?

Yes

To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/9a87a650-d20a-47cd-9806-7a76aba9080en%40googlegroups.com.

[Elaheh Akhoundi]

Many thanks,

best wishes for 2021