[QE-users] Crystal structure changes while doing vc-relax calculation.
Vivek Christhunathan
vivekppn at gmail.com
Tue Feb 1 13:52:26 CET 2022
Hello Everyone,
I'm bringing attention to a topic that has previously been discussed in
this forum. I too faced the same type of problem when I try to do
structural relaxation for CaWO4 (2x1x1 supercell), that its crystal
structure changed from Tetragonal to Orthorhombic. I tried all the
following forum's suggestions to get rid of this problem.
As per their suggestion, I tried using the following tags in my input file,
*>ion_dynamics = 'damp'>and>cell_dynamics = "damp-pr">which should respect
the constraint.*
And also I tried using *cell_dofree=‘ibrav'*. but still lattice parameter
values a and b are not the same. Still, its structure changes from
Tetragonal to Orthorhombic.
*>You can open Modules/cell_base.f90 and at line 84 change>LOGICAL ::
enforce_ibrav = .FALSE.! True if ibrav ...>to>LOGICAL :: enforce_ibrav =
.TRUE.! True if ibrav ...>(do not forget to recompile pw.x) to use
cell_dofree="ibrav" together with any >other cell_dofree*
Since I'm utilizing the Government's supercomputer cluster, I'm not sure
how I'd make these adjustments to the QE code. Can I get your suggestion
regarding this?
*>Should be present in the available patches for v.6.4.1:
filebackports-6.4.1.diff*
<https://github.com/QEF/q-e/releases/download/qe-6.4.1/backports-6.4.1.diff>
in https://github.com/QEF/q-e/releases
Could you please advise me on how to proceed with this link?
I have included calculations input and output for your perusal.
If you could share your thoughts on this issue, that would be quite helpful.
*Input:*
&control
calculation = 'vc-relax'
restart_mode = 'restart'
prefix = 'CaWO4'
tstress = .true.
tprnfor = .true.
pseudo_dir = './'
outdir = './outCaWO4'
wf_collect=.true.
forc_conv_thr = 1d-4
etot_conv_thr = 1D-4
!disk_io = 'medium'
max_seconds = 7200,
/
&system
ibrav = 0
*celldm(1) = 19.820415*
nat = 48
ntyp = 3
ecutwfc = 65.0
ecutrho = 780.0
occupations= 'smearing'
smearing= 'gaussian'
degauss= 0.02
/
&electrons
mixing_beta = 0.2,
conv_thr = 1.0d-6,
electron_maxstep = 50000,
/
&IONS
*ion_dynamics = 'damp'*
/
&cell
cell_factor = 3.0d0
*cell_dynamics = 'damp-pr'*
!cell_dofree= 'ibrav'
/
ATOMIC_SPECIES
Ca 40.08 Ca.pbe-spn-rrkjus_psl.1.0.0.UPF
W 183.84 W.pbe-spn-rrkjus_psl.1.0.0.UPF
O 16.00 O.pbe-n-rrkjus_psl.1.0.0.UPF
*CELL_PARAMETERS (alat)*
* 1.0000000000 0.0000000000 0.0000000000*
* 0.0000000000 0.4999999999 0.0000000000*
* 0.0000000000 0.0000000000 1.0845493931*
ATOMIC_POSITIONS (crystal)
Ca 0.000000000 0.250000000 0.625000000
Ca 0.500000000 0.250000000 0.625000000
Ca 0.000000000 0.750000000 0.375000000
Ca 0.500000000 0.750000000 0.375000000
Ca 0.250000000 0.750000000 0.125000000
Ca 0.750000000 0.750000000 0.125000000
Ca 0.250000000 0.250000000 0.875000000
Ca 0.750000000 0.250000000 0.875000000
W 0.000000000 0.250000000 0.125000000
W 0.500000000 0.250000000 0.125000000
W 0.000000000 0.750000000 0.875000000
W 0.500000000 0.750000000 0.875000000
W 0.250000000 0.750000000 0.625000000
W 0.750000000 0.750000000 0.625000000
W 0.250000000 0.250000000 0.375000000
W 0.750000000 0.250000000 0.375000000
O 0.074850000 0.009300000 0.209700003
O 0.574850023 0.009300000 0.209700003
O 0.425150007 0.990700006 0.790300012
O 0.925150037 0.990700006 0.790300012
O 0.175150007 0.990700006 0.709699988
O 0.675150037 0.990700006 0.709699988
O 0.324849993 0.009300000 0.290300012
O 0.824849963 0.009300000 0.290300012
O 0.370350003 0.399699986 0.459699988
O 0.870350003 0.399699986 0.459699988
O 0.129649997 0.600300014 0.540300012
O 0.629649997 0.600300014 0.540300012
O 0.379649997 0.600300014 0.959699988
O 0.879649997 0.600300014 0.959699988
O 0.120350003 0.399699986 0.040299997
O 0.620350003 0.399699986 0.040299997
O 0.324849993 0.509299994 0.709699988
O 0.824849963 0.509299994 0.709699988
O 0.175150007 0.490700006 0.290300012
O 0.675150037 0.490700006 0.290300012
O 0.425150007 0.490700006 0.209700003
O 0.925150037 0.490700006 0.209700003
O 0.074850000 0.509299994 0.790300012
O 0.574850023 0.509299994 0.790300012
O 0.120350003 0.899699986 0.959699988
O 0.620350003 0.899699986 0.959699988
O 0.379649997 0.100299999 0.040299997
O 0.879649997 0.100299999 0.040299997
O 0.129649997 0.100299999 0.459699988
O 0.629649997 0.100299999 0.459699988
O 0.370350003 0.899699986 0.540300012
O 0.870350003 0.899699986 0.540300012
K_POINTS AUTOMATIC
2 2 2 1 1 1
*Output (a scf loop from output file):*
atom 48 type 3 force = 0.00003185 -0.00002222 -0.00008890
Total force = 0.000633 Total SCF correction = 0.000137
SCF correction compared to forces is large: reduce conv_thr to get
better values
Computing stress (Cartesian axis) and pressure
negative rho (up, down): 1.178E+00 0.000E+00
total stress (Ry/bohr**3) (kbar) P=
0.04
0.00000050 -0.00000019 -0.00000004 0.07 -0.03 -0.01
-0.00000019 0.00000058 -0.00000002 -0.03 0.08 -0.00
-0.00000004 -0.00000002 -0.00000017 -0.01 -0.00 -0.02
number of scf cycles = 14
number of bfgs steps = 13
enthalpy old = -2905.7085634122 Ry
enthalpy new = -2905.7085638929 Ry
CASE: enthalpy_new < enthalpy_old
new trust radius = 0.0005206840 bohr
WARNING! With ibrav=0, cell_dofree='ibrav' does not have any effect.
new conv_thr = 0.0000000100 Ry
new unit-cell volume = 4353.65352 a.u.^3 ( 645.14488 Ang^3 )
density = 5.92862 g/cm^3
*CELL_PARAMETERS (alat= 19.82041500)*
* 1.009431575 0.000035319 0.000001684*
* 0.000017655 0.504836574 0.000001702*
* 0.000001845 0.000003719 1.097205402*
ATOMIC_POSITIONS (crystal)
Ca 0.000001762 0.249997612 0.625000246
Ca 0.500002903 0.249995682 0.624999551
Ca -0.000001762 0.750002388 0.374999754
Ca 0.499997097 0.750004318 0.375000449
Ca 0.249995760 0.750002886 0.125000569
Ca 0.749997044 0.750001219 0.124998286
Ca 0.250002956 0.249998781 0.875001714
Ca 0.750004240 0.249997114 0.874999431
W -0.000007775 0.250005618 0.125011626
W 0.499993856 0.250003532 0.125006749
W 0.000007775 0.749994382 0.874988374
W 0.500006144 0.749996468 0.874993251
W 0.250000614 0.749987294 0.625009963
W 0.750012640 0.750006266 0.625006514
W 0.249987360 0.249993734 0.374993486
W 0.749999386 0.250012706 0.374990037
O 0.074741741 0.007038639 0.209937560
O 0.574740434 0.007045102 0.209936159
O 0.425259596 0.992954904 0.790063856
O 0.925258296 0.992961367 0.790062455
O 0.175252613 0.992959249 0.709941460
O 0.675260736 0.992953207 0.709933905
O 0.324739294 0.007046799 0.290066095
O 0.824747357 0.007040757 0.290058540
O 0.371508681 0.399412719 0.459931561
O 0.871509937 0.399409012 0.459929597
O 0.128490063 0.600590988 0.540070403
O 0.628491319 0.600587281 0.540068439
O 0.378491935 0.600589896 0.959931149
O 0.878493035 0.600590218 0.959930080
O 0.121506965 0.399409782 0.040069905
O 0.621508065 0.399410104 0.040068836
O 0.324753467 0.507030327 0.709936158
O 0.824758249 0.507031484 0.709937563
O 0.175241721 0.492968516 0.290062437
O 0.675246563 0.492969673 0.290063842
O 0.425243174 0.492974405 0.209938014
O 0.925241517 0.492963083 0.209937166
O 0.074758520 0.507036917 0.790062849
O 0.574756856 0.507025595 0.790062001
O 0.121518578 0.899409145 0.959930613
O 0.621518989 0.899409438 0.959931475
O 0.378481011 0.100590547 0.040068510
O 0.878481422 0.100590840 0.040069372
O 0.128480180 0.100591392 0.459933045
O 0.628486141 0.100588990 0.459929416
O 0.371513859 0.899410995 0.540070584
O 0.871519820 0.899408593 0.540066955
Writing output data file CaWO4.save/
NEW-OLD atomic charge density approx. for the potential
negative rho (up, down): 1.178E+00 0.000E+00
extrapolated charge 384.00680, renormalised to 384.00000
total cpu time spent up to now is 3371.9 secs
Self-consistent Calculation
iteration # 1 ecut= 65.00 Ry beta= 0.20
Davidson diagonalization with overlap
ethr = 1.00E-06, avg # of iterations = 2.0
Thanks in advance.
Kind Regards,
Vivek C
__________________________________
Vivek Christhunathan
PhD researcher
Mechanical Engineering
College of Engineering and Informatics
Room 2053
Alice Perry Engineering Building
National University of Ireland Galway
Ireland
E-mail: v.christhunathan1 at nuigalway.ie
Phone: +353 899811181, +91 9600752742
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