[QE-users] Convergency problem

Giovanni Cantele giovanni.cantele at spin.cnr.it
Sat Nov 23 13:20:45 CET 2019


I cannot properly check your input because I don’t have a computer now, however I can suggest to you some things to try and some to be changed.

1) you use PAW pseudo potentials , you should specify ecutrho, since the default value of 4*ecutwfc is much likely insufficient, typical values are from 6 to 12 times ecutwfc, maybe this might result in an uncorverged total charge density

2) also the k-point sampling could be checked against convergence, I would try 2x2x1

3) mixing_beta can be reduced down to 0.01 in the worst cases 

4) maybe it could be worth converging a calculation with no dipole correction, then restart it (calculation=‘restart’) after turning it on, pw.x should not complain as far as I remember

5) increase degauss, converge the calculation with the higher (less converged and more unphysical) smearing and then restart with the initial degauss 

Giovanni

Inviato da iPhone

> Il giorno 23 nov 2019, alle ore 11:15, Ganes Shukri <ganes at tf.itb.ac.id> ha scritto:
> 
> Dear QE users, 
> 
> I am trying to optimize a hexagonal WO3 (001) surface (a quite common system though). However, I am facing difficulty in making the electronic optimization converge (let alone the ionic optimization). I have been trying to change some parameters that may affect the convergency (i.e. mixing_beta, conv_thr, mixing_mode, diagonalization, dipole correction parameters (eamp, emaxpos)), but so far, none is working. The total energy always fluctuates abruptly and does not seem to go to a particular value. I also already used both types of pseudo potential (US and PAW), but still my calculation failed to reach convergency.
> 
> I would be grateful if there are any suggestions or hints from other fellow QE users.
> 
> Below is the (latest) input file that I used and the corresponding structure. 
> 
> -------------------------------------------------------------------------------
> &control
>     calculation='relax'
>     restart_mode='from_scratch'
>     pseudo_dir='/home/hakade/ganes/qe_pp'
>     outdir='./temp'
>     prefix='h-wo3'
>     tprnfor=.true.
>     dipfield=.true.
>     tefield=.true. 
> /
>  &system
>     ibrav=0,
>     nat=102,
>     ntyp=2,
>     ecutwfc=42.0,
>     occupations='smearing',
>     smearing='gauss',
>     degauss=0.02,
>     nspin=1,
>     starting_magnetization(1)=1,
>     edir=3,
>     emaxpos=0.80,
>     eopreg=0.05,
>     eamp=0.00,
>     !lda_plus_u=.TRUE.,
>     !lda_plus_u_kind=0,
>     !Hubbard_U(1)=,
>  /
>  &electrons
>     diagonalization='cg',
>     conv_thr=1.d-4,
>     mixing_beta=0.2,
>     mixing_ndim=8,
>     mixing_mode='local-TF',
>     electron_maxstep=150,
>  /
>  &ions
>     ion_dynamics='bfgs'
>  /
> ATOMIC_SPECIES
> W 183.84 W.pbe-spn-kjpaw_psl.1.0.0.UPF
> O 15.999 O.pbe-n-kjpaw_psl.1.0.0.UPF
> 
> ATOMIC_POSITIONS angstrom
> W	-1.853873	3.211001	18.336259	1	1	1
> W	3.707745	0.000000	18.336259	1	1	1
> W	1.853873	3.211001	18.336259	1	1	1
> W	5.561618	3.211001	18.336259	1	1	1
> W	11.123235	0.000000	18.336259	1	1	1
> W	9.269363	3.211001	18.336259	1	1	1
> W	-1.853873	3.211001	14.525900	1	1	1
> W	3.707745	0.000000	14.525900	1	1	1
> W	1.853873	3.211001	14.525900	1	1	1
> W	5.561618	3.211001	14.525900	1	1	1
> W	11.123235	0.000000	14.525900	1	1	1
> W	9.269363	3.211001	14.525900	1	1	1
> W	-1.853873	3.211001	10.715540	0	0	0
> W	3.707745	0.000000	10.715540	0	0	0
> W	1.853873	3.211001	10.715540	0	0	0
> W	5.561618	3.211001	10.715540	0	0	0
> W	11.123235	0.000000	10.715540	0	0	0
> W	9.269363	3.211001	10.715540	0	0	0
> W	-1.853873	3.211001	6.905180	0	0	0
> W	3.707745	0.000000	6.905180	0	0	0
> W	1.853873	3.211001	6.905180	0	0	0
> W	5.561618	3.211001	6.905180	0	0	0
> W	11.123235	0.000000	6.905180	0	0	0
> W	9.269363	3.211001	6.905180	0	0	0
> O	-1.853873	3.211001	20.241440	1	1	1
> O	3.707745	0.000000	20.241440	1	1	1
> O	1.853873	3.211001	20.241440	1	1	1
> O	5.561618	3.211001	20.241440	1	1	1
> O	11.123235	0.000000	20.241440	1	1	1
> O	9.269363	3.211001	20.241440	1	1	1
> O	0.000000	2.754821	18.336259	1	1	1
> O	3.707745	3.667182	18.336259	1	1	1
> O	5.029745	1.377410	18.336259	1	1	1
> O	-1.322000	5.044592	18.336259	1	1	1
> O	1.322000	5.044592	18.336259	1	1	1
> O	2.385745	1.377410	18.336259	1	1	1
> O	7.415490	2.754821	18.336259	1	1	1
> O	11.123235	3.667182	18.336259	1	1	1
> O	12.445235	1.377410	18.336259	1	1	1
> O	6.093490	5.044592	18.336259	1	1	1
> O	8.737490	5.044592	18.336259	1	1	1
> O	9.801235	1.377410	18.336259	1	1	1
> O	-1.853873	3.211001	16.431080	1	1	1
> O	3.707745	0.000000	16.431080	1	1	1
> O	1.853873	3.211001	16.431080	1	1	1
> O	5.561618	3.211001	16.431080	1	1	1
> O	11.123235	0.000000	16.431080	1	1	1
> O	9.269363	3.211001	16.431080	1	1	1
> O	0.000000	2.754821	14.525900	1	1	1
> O	3.707745	3.667182	14.525900	1	1	1
> O	5.029745	1.377410	14.525900	1	1	1
> O	-1.322000	5.044592	14.525900	1	1	1
> O	1.322000	5.044592	14.525900	1	1	1
> O	2.385745	1.377410	14.525900	1	1	1
> O	7.415490	2.754821	14.525900	1	1	1
> O	11.123235	3.667182	14.525900	1	1	1
> O	12.445235	1.377410	14.525900	1	1	1
> O	6.093490	5.044592	14.525900	1	1	1
> O	8.737490	5.044592	14.525900	1	1	1
> O	9.801235	1.377410	14.525900	1	1	1
> O	-1.853873	3.211001	12.620720	0	0	0
> O	3.707745	0.000000	12.620720	0	0	0
> O	1.853873	3.211001	12.620720	0	0	0
> O	5.561618	3.211001	12.620720	0	0	0
> O	11.123235	0.000000	12.620720	0	0	0
> O	9.269363	3.211001	12.620720	0	0	0
> O	0.000000	2.754821	10.715540	0	0	0
> O	3.707745	3.667182	10.715540	0	0	0
> O	5.029745	1.377410	10.715540	0	0	0
> O	-1.322000	5.044592	10.715540	0	0	0
> O	1.322000	5.044592	10.715540	0	0	0
> O	2.385745	1.377410	10.715540	0	0	0
> O	7.415490	2.754821	10.715540	0	0	0
> O	11.123235	3.667182	10.715540	0	0	0
> O	12.445235	1.377410	10.715540	0	0	0
> O	6.093490	5.044592	10.715540	0	0	0
> O	8.737490	5.044592	10.715540	0	0	0
> O	9.801235	1.377410	10.715540	0	0	0
> O	-1.853873	3.211001	8.810360	0	0	0
> O	3.707745	0.000000	8.810360	0	0	0
> O	1.853873	3.211001	8.810360	0	0	0
> O	5.561618	3.211001	8.810360	0	0	0
> O	11.123235	0.000000	8.810360	0	0	0
> O	9.269363	3.211001	8.810360	0	0	0
> O	0.000000	2.754821	6.905180	0	0	0
> O	3.707745	3.667182	6.905180	0	0	0
> O	5.029745	1.377410	6.905180	0	0	0
> O	-1.322000	5.044592	6.905180	0	0	0
> O	1.322000	5.044592	6.905180	0	0	0
> O	2.385745	1.377410	6.905180	0	0	0
> O	7.415490	2.754821	6.905180	0	0	0
> O	11.123235	3.667182	6.905180	0	0	0
> O	12.445235	1.377410	6.905180	0	0	0
> O	6.093490	5.044592	6.905180	0	0	0
> O	8.737490	5.044592	6.905180	0	0	0
> O	9.801235	1.377410	6.905180	0	0	0
> O	-1.853873	3.211001	5.000000	0	0	0
> O	3.707745	0.000000	5.000000	0	0	0
> O	1.853873	3.211001	5.000000	0	0	0
> O	5.561618	3.211001	5.000000	0	0	0
> O	11.123235	0.000000	5.000000	0	0	0
> O	9.269363	3.211001	5.000000	0	0	0
> 
> CELL_PARAMETERS angstrom
> 14.8309803009 0.0000000000 0.0000000000
> -3.7077450752 6.4220028518 0.0000000000
> 0.00000000000 0.0000000000 35.2414398193
> 
> K_POINTS gamma
> ----------------------------------------------------------------------------------
> 
> cheers,
> 
> Ganes
> 
> 
> ------------------------------------------------------------------------
> -----------------------------------------------------------------------
> Ganes Shukri
> Faculty Member
> Advanced Functional Materials Research Group
> Dept. of Engineering Physics
> Bandung Institute of Technology
> -----------------------------------------------------------------------
> 
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> 
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