[QE-users] vc-relax with PBE0 or HSE is not converging
Giuseppe Mattioli
giuseppe.mattioli at ism.cnr.it
Wed Jun 14 15:46:51 CEST 2023
Dear Salma
I don't know how outdated it is, but there is a README in the
directory of the EXX examples
/path_to_QE_7.2/PW/examples/EXX_example
reporting this:
WHAT PROPERTIES CAN I COMPUTE ?
Energy and forces (thanks to Hellmann-Feynman theorem forces do not
require extra calculations). In principle also stresses but the
corresponding formulas have not yet been coded. <-------!!!!!!!
So structural optimization is OK if the cell shape is kept fixed.
HTH
Giuseppe
Quoting NAIMI SALMA <salma_naimi at um5.ac.ma>:
> Dear all,
>
> I'm doing a vc-relax for my material with hybrid functionals and
> ONCV pseudopotentials.
>
> When the job is done I can't find the optimized final coordinates
> and lattice parameter in the output file , also I noticed that the
> final pressure is positive and not close to zero, as bellow:
>
> Computing stress (Cartesian axis) and pressure
>
> total stress (Ry/bohr**3) (kbar)
> P= 106.49
> 0.00072391 -0.00000000 0.00000000 106.49 -0.00
> 0.00
> -0.00000000 0.00072391 0.00000000 -0.00 106.49
> 0.00
> -0.00000000 -0.00000000 0.00072391 -0.00 -0.00
> 106.49
>
>
> I repeated the calculation so many times by modifying some input
> variables but the same problems always occur for PBE0 and HSE as well.
>
>
> Before the last lines in the output file I find this:
>
>
>
> ...
>
> Input lattice vectors:
>
> -0.50342437 0.00000000 0.50342437
>
> 0.00000000 0.50342437 0.50342437
>
> -0.50342437 0.50342437 0.00000000
>
> New lattice vectors in INITIAL alat:
>
> -0.50342437 0.00000000 0.50342437
>
> 0.00000000 0.50342437 0.50342437
>
> -0.50342437 0.50342437 0.00000000
>
> New lattice vectors in NEW alat (for information only):
>
> -0.50000000 0.00000000 0.50000000
>
> 0.00000000 0.50000000 0.50000000
>
> -0.50000000 0.50000000 0.00000000
>
> Discrepancy in bohr = 0.000000 0.000000 0.000000
>
>
> The maximum number of steps has been reached.
>
>
> End of BFGS Geometry Optimization
>
> new unit-cell volume = 382.92325 a.u.^3 ( 56.74337 Ang^3 )
>
> density = 5.57333 g/cm^3
>
>
> CELL_PARAMETERS (alat= 11.44879234)
>
> -0.503424371 0.000000000 0.503424371
>
> 0.000000000 0.503424371 0.503424371
>
> -0.503424371 0.503424371 0.000000000
>
>
> ATOMIC_POSITIONS (crystal)
>
> ....
>
>
>
> Where this problem is coming from please and how can I fix it?
>
> I attached my input file
>
>
>
>
>
>
>
> ------------------------------------------------------------
> Salma NAIMI
> PhD student - Mohamed 5 University-Rabat
GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <giuseppe.mattioli at ism.cnr.it>
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