[QE-users] syntax of using starting_ns_eigenvalue for two different localized orbitals of the same atom

[Iurii TIMROV]

> However, suppose the Hubbard atom is Ce, "[Xe]6s2 4f1 5d1" with two localized incomplete orbitals of Ce-4f and Ce-5d. Then how can one specify the starting_ns_eigenvalue for both of them with l=3 and l=2?


This is currently not possible to do (not implemented). starting_ns_eigenvalue changes only the eigenvalues of the occupation matrix corresponding to the first Hubbard channel.


Note that applying +U to two Hubbard channels of the same atomic type is a relatively new feature, and hence many things are not supported for this case (like the issue mentioned about).


> It seems that the second localized orbital is treated as "background part" and accidentally(?!) the eigenvectors of its nod-degenerate eigenvalues are set to 1.0 !


The second Hubbard channel can be called "background", but it is nothing but just the second channel. The populations of the first and second Hubbard channels are initialized in the code (PW/src/init_ns.f90) and I do not really understand what is "accidental". If you want to have more precise answers, you should be more specific.


HTH


Iurii


--
Dr. Iurii TIMROV
Senior Research Scientist
Theory and Simulation of Materials (THEOS)
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Mahmoud Payami Shabestari via users <users at lists.quantum-espresso.org>
Sent: Friday, August 12, 2022 7:48:32 AM
To: Mahmoud Payami Shabestari; Quantum ESPRESSO users Forum
Subject: Re: [QE-users] syntax of using starting_ns_eigenvalue for two different localized orbitals of the same atom

It seems that the second localized orbital is treated as "background part" and accidentally(?!) the eigenvectors of its nod-degenerate eigenvalues are set to 1.0 !

mahmoud




From: "Mahmoud Payami Shabestari" <mpayami at aeoi.org.ir>
To: "Quantum ESPRESSO users Forum" <users at lists.quantum-espresso.org>
Date: Fri, 12 Aug 2022 07:32:05 +0430
Subject: Re: [QE-users] syntax of using starting_ns_eigenvalue for two different localized orbitals of the same atom

Dear Stefano,

Hi.
Thank you for your detailed explanation for the Fe case.
However, suppose the Hubbard atom is Ce, "[Xe]6s2 4f1 5d1" with two localized incomplete orbitals of Ce-4f and Ce-5d. Then how can one specify the starting_ns_eigenvalue for both of them with l=3 and l=2?
Thank you in advance.

Best regards,
mahmoud


From: Stefano de Gironcoli <degironc at sissa.it>
To: Mahmoud Payami Shabestari via users <users at lists.quantum-espresso.org>
Date: Thu, 11 Aug 2022 21:19:56 +0200
Subject: Re: [QE-users] syntax of using starting_ns_eigenvalue for two different localized orbitals of the same atom

suppose your Hubbard atom of type 1 is an Fe ( U on 3d orbitals)..., then
starting_ns_eigenvalue(3,1,1)=1.0  overwrites the third eigenvalue of the occupations with spin=1 (up) to 1.0
starting_ns_eigenvalue(4,1,1)=0.3 overwrites the forth eigenvalue of the occupations with spin=1 (up) to 0.3
starting_ns_eigenvalue(5,2,1)=0.0 overwrites the fifth eigenvalue of the occupations with spin=2 (dw) to 0.0
the other elements are left unchanged.
In general at the first iteration the code computes the occupation matrix ns, diagonalizes it, overwrites the eigenvalues if required in input and then calculates the output ns matrix from the (overwritten) eigenvalue decomposition.
if you specify more starting_ns_eigenvalue lines for a given atomic type the code will apply all of them independently
stefano
On 11/08/22 21:00, Mahmoud Payami Shabestari via users wrote:
Dear QE-7.1 Developers,

Hi. I would like to use the starting_ns_eigenvalue()=1.0 for two different localized orbitals of the same atom. I do not have problem in the HUBBARD card, but I do not know how to use starting_ns_eigenvalue()=1.0 for different orbital angular momenta of the same atom.
Any comments is highly appreciated.

Best regards,
Mahmoud Payami


---------------------------------------
Mahmoud Payami
NSTRI, AEOI, Tehran, Iran

Email: mpayami at aeoi.org.ir<mailto:mpayami at aeoi.org.ir>
Phone: +98 (0)21 82066504
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