RPA forces

Queries about input and output files, running specific calculations, etc.


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kdoblhoff
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RPA forces

#1 Post by kdoblhoff » Mon Jul 11, 2022 8:32 am

Dear Vasp developers,
I wanted to ask about the status of RPA forces for metallic systems (finite temperature algorithm). I vaguely remember someone saying a while ago that those were under development. On the website, it still states that forces are not yet available for metallic systems. I assume that this is still the current status, right? (At least I am not aware of any publication related to this.)
Thank you for your reply,
Best regards,
Katharina

merzuk.kaltak
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Re: RPA forces

#2 Post by merzuk.kaltak » Mon Jul 11, 2022 10:19 am

Dear Katharina,

Yes, you are right. RPA forces for metallic systems are still under development and there is no publication about this topic yet.
However, you can use the code in vasp-6.3.2 by setting LRPAFORCE =T and LFINITE_TEMPERATURE=T in the INCAR. Note, latter requires ISMEAR =-1

kdoblhoff
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Re: RPA forces

#3 Post by kdoblhoff » Tue Jul 12, 2022 12:55 pm

If I correctly understand your comment you imply that "at own risk" it can be used for tests, right?

fabien_tran1
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Re: RPA forces

#4 Post by fabien_tran1 » Wed Jul 13, 2022 8:54 am

Yes. There is still some possible uncertainty with the correctness of the implementation of RPA forces for metals.

A good idea would be to check that the geometry obtained after optimization is really a minimum by displacing the atoms (and hopefully observe an increase of the total energy). However, such a check is of course possible only for very simple systems.

Note that there is a test for RPA forces for a metal in the testsuite (FeAl_333_RPAFORCE).

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