Dear "[email protected]", (sorry for the missing character set)
Have you understood which kind of pseudo potentials you have chosen to
use with Quantum ESPRESSO? In particular going from the PAW (most likely,
or ultra-soft pp's) to the FHI pp's shown in your input? Did you check
that the cut-off energy for the wave functions, 'ecutwfc', is sufficient?
I doubt so, if not already for Cr. In principle you do not need to set the
'ecutrho' for the norm-conserving pp's, and do you have a reason to give
an explicit value of 'nbnd' if your system does have a large band gap (I
conclude this because your mixing parametre is loose and you do not use
fractional occupation numbers and still get a converged electronic
structure)?
Once you are well converged in the cut-off energy, you probably want to
relax both the lattice constants and the ionic positions once more with
the present pp's; otherwise your phonon eigenvalues and -vectors are not
that precise because you are not at the minimum of the potential energy
surface, whereas this is assumed (harmonically) when calculating the
phonons.
Good Luck,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari Paavo Seitsonen / [email protected] / http://www.iki.fi/~apsi/
Ecole Normale Supérieure (ENS), Département de Chimie, Paris
Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935
On Wed, 13 May 2015, 杨顶峰 wrote:
Dear All,
I am trying the quantum espresso 5.1 to perform the phonon
calculation of a compound.
firstly, i use VASP to get a better geometry calculation , then the opted
model was used to carried out the self consistent calculation and phonon
calculation on quantum espresso 5.1 .
my input file for the self consistent calculation is given below:
&control
title='sbcrse3'
calculation = 'scf' ,
restart_mode='from_scratch',
wf_collect=.true.,
prefix = 'sbcrse3',
outdir = './',
pseudo_dir = './',
tstress=.true.
tprnfor=.true.
etot_conv_thr=1.0D-6,
forc_conv_thr=1.0D-6,
/
&system
ibrav = 8,
celldm(1) = 17.721473993588537072269931508765,
celldm(2) = 0.40987224478027270642574239356715,
celldm(3) = 1.4354965598661794909645534975973,
nat = 20 ,
ntyp = 3 ,
ecutwfc = 40,
ecutrho = 300,
occupations = 'fixed' ,
nbnd = 150,
/
&electrons
mixing_beta=0.7
conv_thr = 1.0d-10 ,
/
ATOMIC_SPECIES
Sb 121.7 Sb.pbe-mt_fhi.UPF
Se 78.96 Se.pbe-mt_fhi.UPF
Cr 51.996 Cr.pbe-mt_fhi.UPF
ATOMIC_POSITIONS crystal
Sb 0.471599996 0.250000000 0.655629992
Sb 0.528400004 0.750000000 0.344370008
Sb 0.028400004 0.750000000 0.155629992
Sb 0.971599996 0.250000000 0.844370008
.....
K_POINTS automatic
13 13 13 0 0 0
the above calculation was running successfully. the details shows as
follows:
convergence has been achieved in 76 iterations
Forces acting on atoms (Ry/au):
atom 1 type 1 force = 0.00330300 -0.00000173 0.01711914
atom 2 type 1 force = -0.00330300 0.00000173 -0.01711914
atom 3 type 1 force = -0.00330300 0.00000173 0.01711914
atom 4 type 1 force = 0.00330300 -0.00000173 -0.01711914
atom 5 type 2 force = -0.00590819 -0.00028964 0.01684058
........
Total force = 0.064539 Total SCF correction = 0.000006
entering subroutine stress ...
total stress (Ry/bohr**3) (kbar) P=
-77.36
-0.00044232 0.00000132 0.00000000 -65.07 0.19 0.00
0.00000132 -0.00068747 0.00000000 0.19 -101.13 0.00
0.00000000 0.00000000 -0.00044787 0.00 0.00 -65.88
But when i begin the phonon calculation there is a problem, some tips will
be show in the "out " file:
Electric Fields Calculation
ik 1 ibnd 59 linter: root not converged 5.993E-09
ik 1 ibnd 59 linter: root not converged 3.084E-09
ik 2 ibnd 59 linter: root not converged 2.722E-07
ik 2 ibnd 59 linter: root not converged 3.810E-09
ik 2 ibnd 59 linter: root not converged 1.129E-09
ik 3 ibnd 59 linter: root not converged 1.634E-09
ik 3 ibnd 59 linter: root not converged 9.282E-09
ik 3 ibnd 59 linter: root not converged 1.749E-09
ik 4 ibnd 59 linter: root not converged 2.191E-09
ik 4 ibnd 59 linter: root not converged 2.338E-09
ik 4 ibnd 59 linter: root not converged 1.895E-09
ik 5 ibnd 59 linter: root not converged 1.241E-08
ik 5 ibnd 59 linter: root not converged 1.440E-09
ik 5 ibnd 59 linter: root not converged 3.946E-09
ik 6 ibnd 59 linter: root not converged 5.932E-08
ik 6 ibnd 59 linter: root not converged 6.026E-09
ik 6 ibnd 59 linter: root not converged 5.804E-08
ik 7 ibnd 59 linter: root not converged 6.012E-09
ik 7 ibnd 59 linter: root not converged 1.088E-09
ik 7 ibnd 59 linter: root not converged 1.407E-08
ik 8 ibnd 59 linter: root not converged 1.962E-09
................
the calculation is still on progress, i really don`t know how to conquer the
problem as a new beginner, please help me, Thanks a lot!
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