[QE-users] Convergence problem in vc-relax
Lorenzo Bastonero
lbastone at uni-bremen.de
Tue Jul 12 17:49:50 CEST 2022
Hi,
At first look it seems your cutoff is a bit too small, as well as your conv_thr.
Pressure usually is rather affected by low cutoff. I’d expect at least 80/90 Ry cutoff for converged results within sensible parameters.
Best,
Lorenzo
Inviato da iPhone
> Il giorno 12 lug 2022, alle ore 17:40, Ali Jaberi <ali.jaberi at mail.mcgill.ca> ha scritto:
>
>
> Hi,
>
> I am trying to relax the structure for Li(Ni1/3Mn1/3Co1/3)O2. I could relax the structure with VASP but not with Quantum ESPRESSO. I have tried changing so many parameters but could not get any result so end up posting my problem here.
>
> Here is my input file:
>
> -----------------------------------------------------------------------------------------
> &control
> calculation='vc-relax'
> nstep = 500,
> restart_mode = 'from_scratch' ,
> pseudo_dir = '....' ,
> outdir = './outdir'
> prefix = 'NMC',
> verbosity ='high' ,
> tprnfor = .true.
> etot_conv_thr= 1.0D-3
> forc_conv_thr = 1.0D-2
> /
>
> &system
> ibrav = 0,
> nat =36,
> ntyp =5,
> ecutwfc = 34 ,
> ecutrho = 380,
> occupations ='smearing',
> smearing='mv',
> degauss=0.001,
> nspin = 2,
> starting_magnetization(2)=0.7,
> starting_magnetization(3)=0.7,
> starting_magnetization(4)=0.7,
> lda_plus_u = .true.
> Hubbard_U(2)=4.84,
> Hubbard_U(3)=5.0,
> Hubbard_U(4)=5.96,
> /
>
> &electrons
> electron_maxstep = 700
> conv_thr = 1.0d-4,
> mixing_beta = 0.3,
> diagonalization = 'david',
> /
>
> &IONS
> ion_dynamics = "bfgs",
> /
>
> &CELL
> cell_dynamics = 'bfgs'
> press_conv_thr = 0.9
> /
>
> ATOMIC_SPECIES
> Li 6.940 Li.pbe-sl-rrkjus_psl.1.0.0.UPF
> Mn 54.938 Mn.pbe-spn-rrkjus_psl.0.3.1.UPF
> Co 58.933 Co.pbe-spn-rrkjus_psl.0.3.1.UPF
> Ni 58.693 Ni.pbe-spn-rrkjus_psl.1.0.0.UPF
> O 15.999 O.pbe-n-rrkjus_psl.1.0.0.UPF
>
> CELL_PARAMETERS angstrom
> 4.92404724 0.00000000 0.00000000
> -2.46202362 4.26435000 0.00000000
> 0.00000000 0.00000000 14.14560000
>
> ATOMIC_POSITIONS angstrom
> Co -0.81985389 4.26292856 11.78328480
> Co 0.82231591 1.42144999 2.34816960
> Co 2.46202362 4.26435000 7.07280000
> Li 0.00000000 0.00000000 0.00000000
> Li -0.81985389 4.26292856 4.71048480
> Li 0.82231591 1.42144999 9.42096960
> Li -0.00000003 2.84290001 0.00000000
> Li 1.64216978 2.84147854 4.71048480
> Li 3.28433951 0.00000000 9.42096960
> Li 2.46202364 1.42144999 0.00000000
> Li -0.81985387 1.42002855 4.71048480
> Li -1.63970776 2.84290001 9.42096960
> Mn -0.00000003 2.84290001 7.07280000
> Mn 1.64216978 2.84147854 11.78328480
> Mn 3.28433951 0.00000000 2.34816960
> Ni 2.46202364 1.42144999 7.07280000
> Ni -0.81985387 1.42002855 11.78328480
> Ni -1.63970776 2.84290001 2.34816960
> O 0.00000000 0.00000000 3.38910187
> O 0.00000000 0.00000000 10.75649813
> O -0.81985389 4.26292856 8.09958667
> O -0.81985389 4.26292856 1.32138293
> O 0.82231591 1.42144999 12.81007147
> O 0.82231591 1.42144999 6.03186773
> O -0.00000003 2.84290001 3.38910187
> O -0.00000003 2.84290001 10.75649813
> O 1.64216978 2.84147854 8.09958667
> O 1.64216978 2.84147854 1.32138293
> O 3.28433951 0.00000000 12.81007147
> O 3.28433951 0.00000000 6.03186773
> O 2.46202364 1.42144999 3.38910187
> O 2.46202364 1.42144999 10.75649813
> O -0.81985387 1.42002855 8.09958667
> O -0.81985387 1.42002855 1.32138293
> O -1.63970776 2.84290001 12.81007147
> O -1.63970776 2.84290001 6.03186773
>
> K_POINTS automatic
> 4 4 4 0 0 0
> -----------------------------------------------------------------------------------------
>
> Ther pressures I got for this relaxation are very high at each step!!!
>
> total stress (Ry/bohr**3) (kbar) P= -23972.31
> total stress (Ry/bohr**3) (kbar) P= -26659.21
> total stress (Ry/bohr**3) (kbar) P= -24871.74
> total stress (Ry/bohr**3) (kbar) P= -24165.07
> total stress (Ry/bohr**3) (kbar) P= -24040.51
> total stress (Ry/bohr**3) (kbar) P= -23928.12
> total stress (Ry/bohr**3) (kbar) P= -23974.47
> total stress (Ry/bohr**3) (kbar) P= -24023.37
> total stress (Ry/bohr**3) (kbar) P= -24016.41
> total stress (Ry/bohr**3) (kbar) P= -24102.96
> total stress (Ry/bohr**3) (kbar) P= -24097.08
> total stress (Ry/bohr**3) (kbar) P= -24080.78
> total stress (Ry/bohr**3) (kbar) P= -26559.80
> total stress (Ry/bohr**3) (kbar) P= -24814.82
> total stress (Ry/bohr**3) (kbar) P= -24024.82
>
> This is exactly the structure VASP could converge so there should be a problem in the parameters or the algorithm. I really appreciate it if anyone could help me with this.
>
> Best.
> Ali Jaberi
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