Re: [QE-users] Why is my VC-RELAX not showing converged result?
hello,
vc-relax is done at constant fft grid, not constant kineti energy cutoff. At
the end the scf is repeated with the initial cutoff, which can show some
discrepancy if the calculation was not very converged, or if the initial volume
was quite far from the final one. Repeat the vc-relax starting with the final
cell and you should get a perfect result.
hth
--
Lorenzo Paulatto - Paris
On Feb 19 2022, at 5:58 pm, Naharin Jannath
wrote:
> I ran the VC-RELAX for simple niobium until I get a converged value. But at
> the bottom of the output, the cell parameter stops changing. Also, the
> pressure is well below the "pres_conv_thr" which was set to 0.01 in the input
> file. Can anyone tell me how to fix it? Also, my CELL_PARAMETER vs K curve is
> not smooth even using large smearing.
>
> &CONTROL
> calculation = 'vc-relax'
> restart_mode = 'from_scratch'
> prefix = 'Nb'
> etot_conv_thr = 0.01
> pseudo_dir = '.'
> outdir = '.'
> disk_io = 'none'
> tstress = .true.
> tprnfor = .true.
> /
> &SYSTEM
> degauss = 0.05
> ecutrho = 360
> ecutwfc = 45
> ibrav = 0
> nat = 1
> ntyp = 1
> occupations = "smearing"
> smearing = "gaussian"
> /
> &ELECTRONS
> conv_thr = 1.0e-08
> electron_maxstep = 200
> mixing_mode = 'plain'
> mixing_beta = 0.5
> startingpot = "atomic"
> startingwfc = "atomic+random"
> /
> &IONS
> ion_dynamics = "bfgs"
> /
> &CELL
> cell_dynamics = "bfgs"
> press_conv_thr = 0.01
> /
> ATOMIC_SPECIES
> Nb 92.90638 Nb.pbe-spn-kjpaw_psl.0.3.0.UPF
> ATOMIC_POSITIONS {crystal}
> Nb 0.00 0.00 0.00
> CELL_PARAMETERS {angstrom}
> 1.675751271 1.675751271 1.675751271
> -1.675751271 1.675751271 1.675751271
> -1.675751271 -1.675751271 1.675751271
> K_POINTS {automatic}
> 10 10 10 0 0 0
>
>
> output --
> PRESSURE -
> total stress (Ry/bohr**3) (kbar) P= -47.02
> total stress (Ry/bohr**3) (kbar) P= -9.58
> total stress (Ry/bohr**3) (kbar) P= 0.65
> total stress (Ry/bohr**3) (kbar) P= 0.02
> total stress (Ry/bohr**3) (kbar) P= 0.01
> total stress (Ry/bohr**3) (kbar) P= -0.21
>
>
> CELL_PARAMETERS (angstrom)
> 1.662361144 1.662361144 1.662361144
> --
> CELL_PARAMETERS (angstrom)
> 1.659001159 1.659001159 1.659001159
> --
> CELL_PARAMETERS (angstrom)
> 1.659212618 1.659212618 1.659212618
> --
> CELL_PARAMETERS (angstrom)
> 1.659217666 1.659217666 1.659217666
> --
> CELL_PARAMETERS (angstrom)
> 1.659217666 1.659217666 1.659217666
>
> ___
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users@lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users
Re: [QE-users] Why is my VC-RELAX not showing converged result?
Hey!
I suggest you to put in section:
&control
etot_conv_thr =1.d-4 # this one for convergence threshold on total energy for
ionic minimization
forc_conv_thr=1.d-3 #the same thing but convergence threshold on forces
U can put also in section
&electrons
Conv_thr = 1.0e-6
Mixing_beta=0.2
Mixing_mode = “plain”
Mixing_ndim=8
U can check your cell_parameters… its not seems to me that is body cubic center!
Try it and tell me …
Best regards,
Sally
On 19 Feb 2022, at 17:59, Naharin Jannath wrote:
I ran the VC-RELAX for simple niobium until I get a converged value. But at the
bottom of the output, the cell parameter stops changing. Also, the pressure is
well below the "pres_conv_thr" which was set to 0.01 in the input file. Can
anyone tell me how to fix it? Also, my CELL_PARAMETER vs K curve is not smooth
even using large smearing.
&CONTROL
calculation = 'vc-relax'
restart_mode = 'from_scratch'
prefix = 'Nb'
etot_conv_thr = 0.01
pseudo_dir = '.'
outdir = '.'
disk_io = 'none'
tstress = .true.
tprnfor = .true.
/
&SYSTEM
degauss = 0.05
ecutrho = 360
ecutwfc = 45
ibrav = 0
nat = 1
ntyp = 1
occupations = "smearing"
smearing = "gaussian"
/
&ELECTRONS
conv_thr = 1.0e-08
electron_maxstep = 200
mixing_mode = 'plain'
mixing_beta = 0.5
startingpot = "atomic"
startingwfc = "atomic+random"
/
&IONS
ion_dynamics = "bfgs"
/
&CELL
cell_dynamics = "bfgs"
press_conv_thr = 0.01
/
ATOMIC_SPECIES
Nb 92.90638 Nb.pbe-spn-kjpaw_psl.0.3.0.UPF
ATOMIC_POSITIONS {crystal}
Nb 0.00 0.00 0.00
CELL_PARAMETERS {angstrom}
1.675751271 1.675751271 1.675751271
-1.675751271 1.675751271 1.675751271
-1.675751271 -1.675751271 1.675751271
K_POINTS {automatic}
10 10 10 0 0 0
output --
PRESSURE -
total stress (Ry/bohr**3) (kbar) P= -47.02
total stress (Ry/bohr**3) (kbar) P= -9.58
total stress (Ry/bohr**3) (kbar) P= 0.65
total stress (Ry/bohr**3) (kbar) P= 0.02
total stress (Ry/bohr**3) (kbar) P= 0.01
total stress (Ry/bohr**3) (kbar) P= -0.21
CELL_PARAMETERS (angstrom)
1.662361144 1.662361144 1.662361144
--
CELL_PARAMETERS (angstrom)
1.659001159 1.659001159 1.659001159
--
CELL_PARAMETERS (angstrom)
1.659212618 1.659212618 1.659212618
--
CELL_PARAMETERS (angstrom)
1.659217666 1.659217666 1.659217666
--
CELL_PARAMETERS (angstrom)
1.659217666 1.659217666 1.659217666
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users
[QE-users] Why is my VC-RELAX not showing converged result?
I ran the VC-RELAX for simple niobium until I get a converged value. But at
the bottom of the output, the cell parameter stops changing. Also, the
pressure is well below the "pres_conv_thr" which was set to 0.01 in the
input file. Can anyone tell me how to fix it? Also, my CELL_PARAMETER vs K
curve is not smooth even using large smearing.
&CONTROL
calculation = 'vc-relax'
restart_mode = 'from_scratch'
prefix = 'Nb'
etot_conv_thr = 0.01
pseudo_dir = '.'
outdir = '.'
disk_io = 'none'
tstress = .true.
tprnfor = .true.
/
&SYSTEM
degauss = 0.05
ecutrho = 360
ecutwfc = 45
ibrav = 0
nat = 1
ntyp = 1
occupations = "smearing"
smearing = "gaussian"
/
&ELECTRONS
conv_thr = 1.0e-08
electron_maxstep = 200
mixing_mode = 'plain'
mixing_beta = 0.5
startingpot = "atomic"
startingwfc = "atomic+random"
/
&IONS
ion_dynamics = "bfgs"
/
&CELL
cell_dynamics = "bfgs"
press_conv_thr = 0.01
/
ATOMIC_SPECIES
Nb 92.90638 Nb.pbe-spn-kjpaw_psl.0.3.0.UPF
ATOMIC_POSITIONS {crystal}
Nb 0.00 0.00 0.00
CELL_PARAMETERS {angstrom}
1.675751271 1.675751271 1.675751271
-1.675751271 1.675751271 1.675751271
-1.675751271 -1.675751271 1.675751271
K_POINTS {automatic}
10 10 10 0 0 0
output --
PRESSURE -
total stress (Ry/bohr**3) (kbar) P= -47.02
total stress (Ry/bohr**3) (kbar) P= -9.58
total stress (Ry/bohr**3) (kbar) P= 0.65
total stress (Ry/bohr**3) (kbar) P= 0.02
total stress (Ry/bohr**3) (kbar) P= 0.01
total stress (Ry/bohr**3) (kbar) P= -0.21
CELL_PARAMETERS (angstrom)
1.662361144 1.662361144 1.662361144
--
CELL_PARAMETERS (angstrom)
1.659001159 1.659001159 1.659001159
--
CELL_PARAMETERS (angstrom)
1.659212618 1.659212618 1.659212618
--
CELL_PARAMETERS (angstrom)
1.659217666 1.659217666 1.659217666
--
CELL_PARAMETERS (angstrom)
1.659217666 1.659217666 1.659217666
___
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users
