[QE-users] [EXTERNAL] The phonon code with Raman and Hubbard U is not implemented

[Lorenzo Paulatto]

On 11/05/2023 17:28, Lorenzo Bastonero wrote:
> Dear Rijan,
>
> To warn you: these steps are involved, and you might need to code 
> quite a bit and have to know the theory behind. Refer to the before 
> mentioned paper.


There is a half-way solution, which consists in doing numerical 
derivatives of the dielectric constants. This works with LDA+U with 
"Atomic" type projections, but not LDA+U+V.

I did a tutorial (very simplified) a few years ago, it shoudl be here:

https://drive.google.com/drive/folders/0Bzgwv8VZEl9SRDQwckRJVlkyUzA?resourcekey=0-BnSQk84YUeRvCNze9XKCAA&usp=sharing

hth


>
> If you are willing to do so, you can find the first steps in example 
> 10 of PW 
> (https://gitlab.com/QEF/q-e/-/tree/develop/PW/examples/example10).
>
> Then you might try to have a look in the PHonon/FD module 
> (https://gitlab.com/QEF/q-e/-/tree/develop/PHonon/FD).
>
> All the best,
> Lorenzo
>
> ********************************
> Lorenzo Bastonero
>
> PhD Student
> U Bremen Excellence Chair,
> Bremen Center for Computational Materials Science,
> and MAPEX Center for Materials and Processes
>
> University of Bremen
> Faculty of Production Engineering
> TAB-Building, Room 3.32
> Am Fallturm 1
> 28359 Bremen, DE
>
> http://www.hmi.uni-bremen.de/
>
>> Il giorno 11 mag 2023, alle ore 16:13, Karkee, Rijan 
>> <rkarkee at lanl.gov> ha scritto:
>>
>> Hi Lorenzo,
>>
>> Thanks for the information. May I know, for now, what steps are 
>> involved so that I can compute those steps by hand?
>> I want to know which module to run first and what would be the input 
>> file should include and likewise for the next steps.
>>
>> Thank you so much.
>>
>> Best
>> Rijan Karkee
>>
>>
>> ------------------------------------------------------------------------
>> *From:*Lorenzo Bastonero <lbastone at uni-bremen.de>
>> *Sent:*Thursday, May 11, 2023 2:11:28 AM
>> *To:*Karkee, Rijan; Quantum ESPRESSO users Forum
>> *Subject:*[EXTERNAL] Re: [QE-users] The phonon code with Raman and 
>> Hubbard U is not implemented
>> Dear Rijan,
>>
>> Indeed the computation of Raman intensities is limited to LDA and 
>> Norm-conserving pseudopotentials.
>>
>> There is an alternative way to compute both phonons (i.e. peak 
>> positions) and intensities (of each mode).
>> You have to use finite differences for the phonons and finite 
>> electric fields for the intensities (if you want to know the theory, 
>> look at Umari and Pasquarello, Diamonds and Related Materials, 2005).
>>
>> These routines are in QE, nevertheless you will need to do the steps 
>> by hand.
>>
>> Currently, we have an automated workflow for doing such calculations 
>> in AiiDA, which is a workflow manager that automates complex 
>> workflows, for QE and other quantum codes.
>> The code will be published very soon, and we plan to send an email 
>> here once it is published.
>>
>> So, at the moment, if you are interested, you can have a look at the 
>> demonstration of AiiDA + QE 
>> (https://aiida-qe-demo.readthedocs.io/en/latest/ 
>> <https://urldefense.com/v3/__https://aiida-qe-demo.readthedocs.io/en/latest/__;!!Bt8fGhp8LhKGRg!DbwBeLMmYIrnyC7VLd4-orYpVCYS7spvVhPfEFwHggBVJv_I2o5dKspdMRW5DKNYoiAGAqSmJ1WuS7chcG1yAe8$>), 
>> and then get your local implementation and install aiida 
>> (https://aiida.net 
>> <https://urldefense.com/v3/__https://aiida.net__;!!Bt8fGhp8LhKGRg!DbwBeLMmYIrnyC7VLd4-orYpVCYS7spvVhPfEFwHggBVJv_I2o5dKspdMRW5DKNYoiAGAqSmJ1WuS7ch19tOXhM$>) 
>> aiida-quantum espresso, which is the main block for the future 
>> package we will release.
>>
>> HTH,
>> Lorenzo
>>
>> Inviato da iPhone
>>
>>> Il giorno 11 mag 2023, alle ore 07:55, Karkee, Rijan via users 
>>> <users at lists.quantum-espresso.org> ha scritto:
>>>
>>> 
>>> Hello Developers,
>>>
>>> I saw some plots of Raman spectra in the tutorial on DFT+U.  I was 
>>> wondering if Raman spectra with DFT+U and/or DFT+U+V will be 
>>> implemented anytime soon or if is there any simpler way to add in 
>>> the code in order for it to have Raman with DFT+U?
>>> As of now, I found that Raman is not implemented with DFT+U.
>>>
>>> Thank you,
>>> Best
>>> Rijan Karkee
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>
>
> _______________________________________________
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
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-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université
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