[QE-users] Last SCF step of a vc-relax job in DFT+U

[Mahmoud Payami Shabestari]

I found the following statement in release-notes:



New in 6.7 version:
  * In vc-relax with Hubbard corrections, the final SCF calculation is done 
by
    reading atomic occupations from file produced during the vc-relax
    (rather than recomputing them from scratch).



What are the advantages of this choice? Does it inform about possible 
transition among metastable states?



Mahmoud

From: "Mahmoud Payami Shabestari" <mpayami at aeoi.org.ir>
To: "users at lists.quantum-espresso.org" <users at lists.quantum-espresso.org>
Date: Wed, 30 Nov 2022 10:49:09 +0330
Subject: [QE-users] Last SCF step of a vc-relax job in DFT+U


Dear All,
Hi.


As far as I know from, in a vc-relax job for a normal system, when the 
calculated pressure in the last scf (which starts with optimized lattice 
parameters and atomic positions, while keeping other input values fixed) is 
much higher than default 0.5kbar value, it implies that one has to increase 
ecutwfc, ecutrho, ... until this large difference disappears.
In a DFT+U run, I encountered such a problem. But when I performed a 
separate scf but with optimized cell parameters and atomic positions, I get 
the optimized value for pressure say 0.01 kbar, which is perfect. I am using 
QE-7.1.
Does it mean that in the last scf run of vc-relax the diagonalised 
ocuupation matrices are used instead of the values specified in the input?
Thanks in advance.


Best regards,
Mahmoud Payami
NSTRI, AEOI, Tehran, Iran


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