My Community

Hello,

I met a big business. When I use vasp6.1.2 and vasp6.2.1 to calculate the same material based on the same initial files "POSCAR,INCAR,POTCAR and KPOINTS", respectively, the result file "vasprun.xml" is different. Then the phonon frequencies in gama point are also different. Why?
======================================================================================================
The following is the first 50 lines from file "vasprun.xml" of vasp6.1.2
------------------------------------------------------------------------------------
</generator>
<incar>
<i type="string" name="PREC"> ACCURATE</i>
<i type="int" name="IBRION"> 8</i>
<i name="EDIFF"> 0.00000000</i>
<i name="EDIFFG"> -0.00000100</i>
<i type="int" name="NSW"> 1</i>
<i name="ENCUT"> 500.00000000</i>
<i type="int" name="ISMEAR"> 0</i>
<i name="SIGMA"> 0.10000000</i>
<i name="EDIFF"> 0.00000000</i>
<i type="int" name="IVDW"> 1</i>
</incar>
<structure name="primitive_cell" >
<crystal>
<varray name="basis" >
<v> 0.00000000 3.64219267 0.00000000 </v>
<v> 3.64219267 0.00000000 0.00000000 </v>
<v> -7.54017350 -7.54017350 -15.79925472 </v>
</varray>
<i name="volume"> 209.58607939 </i>
<varray name="rec_basis" >
<v> 0.00000000 0.27455988 -0.13103334 </v>
<v> 0.27455988 0.00000000 -0.13103334 </v>
<v> 0.00000000 0.00000000 -0.06329412 </v>
</varray>
</crystal>
<varray name="positions" >
<v> 0.38320850 0.88320861 0.18985002 </v>
<v> 0.88320861 0.38320850 0.18985002 </v>
<v> 0.43423465 0.17418416 0.15169043 </v>
<v> 0.17418416 0.43423465 0.15169043 </v>
<v> 0.09223212 0.09223209 0.22800953 </v>
<v> 0.83218211 0.83218211 0.22800968 </v>
</varray>
</structure>
<varray name="primitive_index" >
<v type="int" > 1 </v>
<v type="int" > 10 </v>
<v type="int" > 19 </v>
<v type="int" > 30 </v>
======================================================================================================
The following is the first 50 lines from file "vasprun.xml" of vasp6.2.1.
------------------------------------------------------------------------------------
</generator>
<incar>
<i type="string" name="PREC">ACCURATE</i>
<i type="int" name="IBRION"> 8</i>
<i name="EDIFF"> 0.00000000</i>
<i name="EDIFFG"> -0.00000100</i>
<i type="int" name="NSW"> 1</i>
<i name="ENCUT"> 500.00000000</i>
<i type="int" name="ISMEAR"> 0</i>
<i name="SIGMA"> 0.10000000</i>
<i type="int" name="IVDW"> 1</i>
</incar>
<primitive_cell>
<structure name="primitive_cell" >
<crystal>
<varray name="basis" >
<v> -3.64219267 0.00000000 0.00000000 </v>
<v> 0.00000000 -3.64219267 0.00000000 </v>
<v> 0.25578816 0.25578816 15.79925472 </v>
</varray>
<i name="volume"> 209.58607939 </i>
<varray name="rec_basis" >
<v> -0.27455988 0.00000000 0.00444509 </v>
<v> 0.00000000 -0.27455988 0.00444509 </v>
<v> 0.00000000 0.00000000 0.06329412 </v>
</varray>
</crystal>
<varray name="positions" >
<v> 0.49649143 0.99649153 0.81014998 </v>
<v> 0.99649153 0.49649143 0.81014998 </v>
<v> 0.12919671 0.86914622 0.84830957 </v>
<v> 0.86914622 0.12919671 0.84830957 </v>
<v> 0.36378697 0.36378694 0.77199047 </v>
<v> 0.62383724 0.62383724 0.77199032 </v>
</varray>
</structure>
<varray name="primitive_index" >
<v type="int" > 1 </v>
<v type="int" > 10 </v>
<v type="int" > 19 </v>
<v type="int" > 30 </v>

Can you provide me with the input files so that I can reproduce the issue?

Note that occasionally differences are expected, because the results are only well defined up to a phase/sign, so I would need to know how different your results are to assess whether this may point to an error.

Thank you very much. The following is the four files and "vdw_kernel.bindat" is used.
*****************************************************
POSCAR file
generated by phonopy
1.0
10.9265780164746662 0.0000000000000000 0.0000000000000000
0.0000000000000000 10.9265780164746662 0.0000000000000000
-3.3864045129800884 -3.3864045129800884 15.7992547246839958
C
54
Direct
0.1045528523073382 0.2712194833056761 0.8101499819778368
0.4378861856406715 0.2712194833056761 0.8101499819778368
0.7712195189740048 0.2712194833056761 0.8101499819778368
0.1045528523073382 0.6045528166390094 0.8101499819778368
0.4378861856406715 0.6045528166390094 0.8101499819778368
0.7712195189740048 0.6045528166390094 0.8101499819778368
0.1045528523073382 0.9378861499723428 0.8101499819778368
0.4378861856406715 0.9378861499723428 0.8101499819778368
0.7712195189740048 0.9378861499723428 0.8101499819778368
0.2712194833056761 0.1045528523073382 0.8101499819778368
0.6045528166390094 0.1045528523073382 0.8101499819778368
0.9378861499723428 0.1045528523073382 0.8101499819778368
0.2712194833056761 0.4378861856406715 0.8101499819778368
0.6045528166390094 0.4378861856406715 0.8101499819778368
0.9378861499723428 0.4378861856406715 0.8101499819778368
0.2712194833056761 0.7712195189740048 0.8101499819778368
0.6045528166390094 0.7712195189740048 0.8101499819778368
0.9378861499723428 0.7712195189740048 0.8101499819778368
0.2397042867379919 0.3263877840779182 0.8483095681389585
0.5730376200713252 0.3263877840779182 0.8483095681389585
0.9063709534046585 0.3263877840779182 0.8483095681389585
0.2397042867379919 0.6597211174112516 0.8483095681389585
0.5730376200713252 0.6597211174112516 0.8483095681389585
0.9063709534046585 0.6597211174112516 0.8483095681389585
0.2397042867379919 0.9930544507445849 0.8483095681389585
0.5730376200713252 0.9930544507445849 0.8483095681389585
0.9063709534046585 0.9930544507445849 0.8483095681389585
0.3263877840779182 0.2397042867379919 0.8483095681389585
0.6597211174112516 0.2397042867379919 0.8483095681389585
0.9930544507445849 0.2397042867379919 0.8483095681389585
0.3263877840779182 0.5730376200713252 0.8483095681389585
0.6597211174112516 0.5730376200713252 0.8483095681389585
0.9930544507445849 0.5730376200713252 0.8483095681389585
0.3263877840779182 0.9063709534046585 0.8483095681389585
0.6597211174112516 0.9063709534046585 0.8483095681389585
0.9930544507445849 0.9063709534046585 0.8483095681389585
0.1360678326342963 0.1360678436438765 0.7719904697675872
0.4694011659676297 0.1360678436438765 0.7719904697675872
0.8027344993009630 0.1360678436438765 0.7719904697675872
0.1360678326342963 0.4694011769772098 0.7719904697675872
0.4694011659676297 0.4694011769772098 0.7719904697675872
0.8027344993009630 0.4694011769772098 0.7719904697675872
0.1360678326342963 0.8027345103105432 0.7719904697675872
0.4694011659676297 0.8027345103105432 0.7719904697675872
0.8027344993009630 0.8027345103105432 0.7719904697675872
0.0493843605078344 0.0493843605078344 0.7719903229185761
0.3827176938411677 0.0493843605078344 0.7719903229185761
0.7160510271745011 0.0493843605078344 0.7719903229185761
0.0493843605078344 0.3827176938411677 0.7719903229185761
0.3827176938411677 0.3827176938411677 0.7719903229185761
0.7160510271745011 0.3827176938411677 0.7719903229185761
0.0493843605078344 0.7160510271745011 0.7719903229185761
0.3827176938411677 0.7160510271745011 0.7719903229185761
0.7160510271745011 0.7160510271745011 0.7719903229185761
--------------------------------------------------------------------------
INCAR file
EDIFF = 1E-9
EDIFFG = -1E-6
PREC = ACCURATE
NSW = 1
IBRION = 8
ENCUT = 500
ISMEAR = 0
SIGMA = 0.1
!SYMPREC = 1e-4
!LREAL = Auto
!NCORE = 4
IVDW = 1
------------------------------------------------
KPOINTS file
K-Points
0
Gama-Centered !Monkhorst-Pack
15 15 1
0 0 0
-----------------------------------------------
POTCAR file of the first 50 lines, and you will know it.
PAW_PBE C 08Apr2002
4.00000000000000
parameters from PSCTR are:
VRHFIN =C: s2p2
LEXCH = PE
EATOM = 147.1560 eV, 10.8157 Ry

TITEL = PAW_PBE C 08Apr2002
LULTRA = F use ultrasoft PP ?
IUNSCR = 1 unscreen: 0-lin 1-nonlin 2-no
RPACOR = 1.200 partial core radius
POMASS = 12.011; ZVAL = 4.000 mass and valenz
RCORE = 1.500 outmost cutoff radius
RWIGS = 1.630; RWIGS = 0.863 wigner-seitz radius (au A)
ENMAX = 400.000; ENMIN = 300.000 eV
ICORE = 2 local potential
LCOR = T correct aug charges
LPAW = T paw PP
EAUG = 644.873
DEXC = 0.000
RMAX = 1.529 core radius for proj-oper
RAUG = 1.300 factor for augmentation sphere
RDEP = 1.501 radius for radial grids
RDEPT = 1.300 core radius for aug-charge

Atomic configuration
4 entries
n l j E occ.
1 0 0.50 -273.3789 2.0000
2 0 0.50 -13.7508 2.0000
2 1 0.50 -5.2854 2.0000
3 2 1.50 -5.4423 0.0000
Description
l E TYP RCUT TYP RCUT
0 -13.7508458 23 1.200
0 -8.2022199 23 1.200
1 -5.2854383 23 1.500
1 34.0145650 23 1.500
2 -5.4423304 7 1.500
Error from kinetic energy argument (eV)
NDATA = 100
STEP = 20.000 1.050
51.3 49.5 48.6 46.8 45.9 44.1 42.4 41.6
39.9 38.2 37.4 35.8 34.3 32.8 31.4 30.0
28.6 27.3 26.1 24.3 23.2 22.1 20.5 19.6
18.6 17.3 16.0 15.2 14.1 13.1 12.1 11.1
10.3 9.47 8.72 8.02 7.15 6.55 5.82 5.31
4.69 4.13 3.63 3.17 2.76 2.40 2.07 1.72
1.47 1.20 0.971 0.815 0.650 0.512 0.380 0.292
0.222 0.158 0.110 0.748E-01 0.504E-01 0.337E-01 0.227E-01 0.149E-01
--------------------------------------------------------------------------
vdw_kernel.bindat file which is downloaded from vasp.at

Could you be a bit more specific what the exact problem is? How large are the actual differences in the phonon frequencies?

Can you reproduce this in a smaller system as well?

The following files were used to calculate the FORCECONSTANT and phonon frequencies. It will spend about 8 hours at 28 cores parallelly.The phonon frequencies are different for two edition.
==========================================================================================
phonon frequency at Gama point with vasp 6.1.2
--------------------------------------------------------------
# 0.00000000 0.14505300 0.24762090 0.35018890
0.000000 -0.073931
0.000000 -0.073931
0.000000 0.052147
0.000000 292.936629
0.000000 310.583907
0.000000 382.822745
0.000000 382.822745
0.000000 574.064466
0.000000 574.064466
0.000000 695.872469
0.000000 804.378011
0.000000 907.483772
0.000000 933.626527
0.000000 988.182346
0.000000 988.182346
0.000000 1112.209509
0.000000 1137.997528
0.000000 1154.632523
0.000000 1154.632523
0.000000 1185.583079
0.000000 1185.583079
0.000000 1250.749154
0.000000 1604.891792
0.000000 1734.053669
==========================================================================================
phonon frequency at Gama point with vasp 6.2.1
--------------------------------------------------------------
# 0.00000000 0.14505300 0.24762090 0.35018890
0.000000 -0.004136
0.000000 -0.003303
0.000000 -0.003303
0.000000 137.293743
0.000000 145.564444
0.000000 179.421501
0.000000 179.421501
0.000000 269.052720
0.000000 269.052720
0.000000 326.141812
0.000000 376.996209
0.000000 425.319972
0.000000 437.572526
0.000000 463.141794
0.000000 463.141794
0.000000 521.270893
0.000000 533.357250
0.000000 541.153751
0.000000 541.153751
0.000000 555.659639
0.000000 555.659639
0.000000 586.201741
0.000000 752.181493
0.000000 812.717127
======================================================================
POSCAR
--------------------------------------------
C
1.0
14.6244522550145817 0.0000000000000000 0.0000000000000000
0.0000000000000000 14.6244522550145817 0.0000000000000000
0.0000000000000000 0.0000000000000000 10.8628307751577946
C
72
Direct
0.0008106327990921 0.3325227005342413 0.0263675062578486
0.3341439661324254 0.3325227005342413 0.0263675062578486
0.6674772994657587 0.3325227005342413 0.0263675062578486
0.0008106327990921 0.6658560338675746 0.0263675062578486
0.3341439661324254 0.6658560338675746 0.0263675062578486
0.6674772994657587 0.6658560338675746 0.0263675062578486
0.0008106327990921 0.9991893672009079 0.0263675062578486
0.3341439661324254 0.9991893672009079 0.0263675062578486
0.6674772994657587 0.9991893672009079 0.0263675062578486
0.1010710776987006 0.3325227005342413 0.0263675460062345
0.4344044110320340 0.3325227005342413 0.0263675460062345
0.7677377443653673 0.3325227005342413 0.0263675460062345
0.1010710776987006 0.6658560338675746 0.0263675460062345
0.4344044110320340 0.6658560338675746 0.0263675460062345
0.7677377443653673 0.6658560338675746 0.0263675460062345
0.1010710776987006 0.9991893672009079 0.0263675460062345
0.4344044110320340 0.9991893672009079 0.0263675460062345
0.7677377443653673 0.9991893672009079 0.0263675460062345
0.0008106327990921 0.2322622645513282 0.0263675460062345
0.3341439661324254 0.2322622645513282 0.0263675460062345
0.6674772994657587 0.2322622645513282 0.0263675460062345
0.0008106327990921 0.5655955978846615 0.0263675460062345
0.3341439661324254 0.5655955978846615 0.0263675460062345
0.6674772994657587 0.5655955978846615 0.0263675460062345
0.0008106327990921 0.8989289312179949 0.0263675460062345
0.3341439661324254 0.8989289312179949 0.0263675460062345
0.6674772994657587 0.8989289312179949 0.0263675460062345
0.1010710874672635 0.2322622637673485 0.0263675062578486
0.4344044208005968 0.2322622637673485 0.0263675062578486
0.7677377541339302 0.2322622637673485 0.0263675062578486
0.1010710874672635 0.5655955971006819 0.0263675062578486
0.4344044208005968 0.5655955971006819 0.0263675062578486
0.7677377541339302 0.5655955971006819 0.0263675062578486
0.1010710874672635 0.8989289304340152 0.0263675062578486
0.4344044208005968 0.8989289304340152 0.0263675062578486
0.7677377541339302 0.8989289304340152 0.0263675062578486
0.1674772985972718 0.0655956063073333 0.0263675062578486
0.5008106319306052 0.0655956063073333 0.0263675062578486
0.8341439652639385 0.0655956063073333 0.0263675062578486
0.1674772985972718 0.3989289396406666 0.0263675062578486
0.5008106319306052 0.3989289396406666 0.0263675062578486
0.8341439652639385 0.3989289396406666 0.0263675062578486
0.1674772985972718 0.7322622729739999 0.0263675062578486
0.5008106319306052 0.7322622729739999 0.0263675062578486
0.8341439652639385 0.7322622729739999 0.0263675062578486
0.2677377516222232 0.0655955906278033 0.0263675460062345
0.6010710849555565 0.0655955906278033 0.0263675460062345
0.9344044182888899 0.0655955906278033 0.0263675460062345
0.2677377516222232 0.3989289239611367 0.0263675460062345
0.6010710849555565 0.3989289239611367 0.0263675460062345
0.9344044182888899 0.3989289239611367 0.0263675460062345
0.2677377516222232 0.7322622572944700 0.0263675460062345
0.6010710849555565 0.7322622572944700 0.0263675460062345
0.9344044182888899 0.7322622572944700 0.0263675460062345
0.1674772985417240 0.1658560527004317 0.0263675460062345
0.5008106318750573 0.1658560527004317 0.0263675460062345
0.8341439652083906 0.1658560527004317 0.0263675460062345
0.1674772985417240 0.4991893860337650 0.0263675460062345
0.5008106318750573 0.4991893860337650 0.0263675460062345
0.8341439652083906 0.4991893860337650 0.0263675460062345
0.1674772985417240 0.8325227193670983 0.0263675460062345
0.5008106318750573 0.8325227193670983 0.0263675460062345
0.8341439652083906 0.8325227193670983 0.0263675460062345
0.2677377494308881 0.1658560526448861 0.0263675062578486
0.6010710827642214 0.1658560526448861 0.0263675062578486
0.9344044160975548 0.1658560526448861 0.0263675062578486
0.2677377494308881 0.4991893859782195 0.0263675062578486
0.6010710827642214 0.4991893859782195 0.0263675062578486
0.9344044160975548 0.4991893859782195 0.0263675062578486
0.2677377494308881 0.8325227193115529 0.0263675062578486
0.6010710827642214 0.8325227193115529 0.0263675062578486
0.9344044160975548 0.8325227193115529 0.0263675062578486
===================================================================
INCAR
---------------------------------
EDIFF = 1E-8
EDIFFG = -1E-5
PREC = ACCURATE
NSW = 1
IBRION = 8
ENCUT = 400
ISMEAR = 0
SIGMA = 0.1
SYMPREC = 1e-4
!LREAL = Auto
!NCORE = 4
===================================================================
KPOINTS
---------------------------------
K-Points
0
Gama-Centered !Monkhorst-Pack
15 15 1
0 0 0
===================================================================
POTCAR , you will know the details.
---------------------------------
PAW_PBE C 08Apr2002
4.00000000000000
parameters from PSCTR are:
VRHFIN =C: s2p2
LEXCH = PE
EATOM = 147.1560 eV, 10.8157 Ry

TITEL = PAW_PBE C 08Apr2002
LULTRA = F use ultrasoft PP ?
IUNSCR = 1 unscreen: 0-lin 1-nonlin 2-no
RPACOR = 1.200 partial core radius
POMASS = 12.011; ZVAL = 4.000 mass and valenz
RCORE = 1.500 outmost cutoff radius
RWIGS = 1.630; RWIGS = 0.863 wigner-seitz radius (au A)
ENMAX = 400.000; ENMIN = 300.000 eV
ICORE = 2 local potential
LCOR = T correct aug charges
LPAW = T paw PP
EAUG = 644.873
DEXC = 0.000
RMAX = 1.529 core radius for proj-oper
RAUG = 1.300 factor for augmentation sphere
RDEP = 1.501 radius for radial grids
RDEPT = 1.300 core radius for aug-charge

Atomic configuration
4 entries
n l j E occ.
1 0 0.50 -273.3789 2.0000
2 0 0.50 -13.7508 2.0000
2 1 0.50 -5.2854 2.0000
3 2 1.50 -5.4423 0.0000
Description
l E TYP RCUT TYP RCUT
0 -13.7508458 23 1.200
0 -8.2022199 23 1.200
1 -5.2854383 23 1.500
1 34.0145650 23 1.500
2 -5.4423304 7 1.500
Error from kinetic energy argument (eV)
NDATA = 100
...

The frequencies unit at Gama point is cm-1.

Okay that is definitely a larger difference in the frequency that one would expect. I will investigate this.

What you can try is to use IBRION=6 instead. The finite difference approach is much more robust and will work for many more methods. Perhaps the issue is an incompatibility of perturbation theory and van der Waals functionals.