[Pw_forum] convergence can't achieved with QE6.0.2 and 5.4.0

[Matteo Cococcioni]

I'm pretty sure forces and stresses were tested in all +U flavors, at least
for the version of the code where they were originally implemented.
It is true that +U typically leads to the creation of several local minima
and maybe this makes the convergence harder. However, I have never seen
a total force staying so constant (and big) as you show. Are the ions
moving at all? How big is your trust radius?
Does the relaxation converge if you set Hubbard_J0 = 0?
Also, is "exxdiv_treatment = 'gygi-baldereschi' " needed?

Matteo


On Fri, May 5, 2017 at 10:37 AM, Lorenzo Paulatto <
lorenzo.paulatto at impmc.upmc.fr> wrote:

> On Friday, 5 May 2017 09:26:53 CEST Q.J.Wang wrote:
> >              lda_plus_u_kind = 0 ,
> >                 Hubbard_U(3) = 4.5,
> >                Hubbard_J0(3) = 0.5,
> >...
> > The total force seems nearly invariable. I also use QE5.4.0 to run the
> input
> > file, the total force still can't  converge after 300 scf cycles and  2
> bfgs
> > steps.
>
> My guess is that there is an inconsistency between LDA+U energy and forces,
> which prevents the BFGS calculation from converging.
>
> kind regards
>
> --
> Dr. Lorenzo Paulatto
> IdR @ IMPMC -- CNRS & Université Paris 6
> phone: +33 (0)1 442 79822 / skype: paulatz
> www:   http://www-int.impmc.upmc.fr/~paulatto/
> mail:  23-24/423 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
>
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