Hello everyone,
Recently, I did some calculation to compare the performace of qe and vasp. I
find that the relative energies of pure dft of qe and vasp are quite
consistent, and there are some differences between the forces on atoms. But as
to the stress tensors, the differences are large.
Below is the result data of one case (kbar)
==============================================
qe:
xx xz yx xy
ecutwfc_45Ry 11.83 5.92 9.02 -8.92
ecutwfc_50Ry 14.92 9.34 12.1 -8.75
ecutwfc_55Ry 13.16 7.61 10.33 -8.73
ecutwfc_60Ry 11.95 6.39 9.12 -8.73
ecutwfc_65Ry 12.03 6.47 9.21 -8.74
ecutwfc_70Ry 12.87 7.31 10.05 -8.74
ecutwfc_75Ry 13.89 8.36 11.08 -8.72
ecutwfc_80Ry 14.75 9.23 11.93 -8.71
==============================================
vasp:
Direction XX YY ZZ XY
ecutwfc_520ev 8.01175 1.70119 5.24923 -7.42910
ecutwfc_800ev 8.44879 1.99011 5.69489 -7.34710
==============================================
What I am curious about is the possiable reasons which make the result
differences of the qe and vasp. Surely, psuedopotentials is one of the reasons.
I expected the stress tensors are consistent like the relative energy results
during the calculations, but it is not.
Happy to recevie any ideas about it.
The vasp INCAR file and qe input file are attached. best, Fang Liwen
INCAR
Description: Binary data
&CONTROL
calculation = 'scf',
tstress = .true.,
tprnfor = .true.,
restart_mode = 'from_scratch',
outdir = './',
pseudo_dir = '/home/corp/liwen.fang/software/qe/paw',
prefix = 'st',
disk_io = 'none',
etot_conv_thr = 0.00010000,
forc_conv_thr = 0.00100000,
nstep = 200,
/
&SYSTEM
ibrav = 0,
nat = 72,
ntyp = 4,
tot_charge = 0.00000000,
ecutwfc = 60,
ecutrho = 600,
occupations = 'smearing',
degauss = 0.01000000,
smearing = 'gaussian',
nspin = 1,
assume_isolated = 'none',
input_dft = 'pbe',
starting_magnetization(1) = 0.20000000,
starting_magnetization(2) = 0.20000000,
starting_magnetization(3) = 0.20000000,
starting_magnetization(4) = 0.20000000,
nbnd =199,
/
&ELECTRONS
electron_maxstep = 200,
conv_thr = 0.0000000100,
mixing_beta = 0.70000000,
mixing_mode = 'local-TF',
diagonalization = 'ppcg',
/
&IONS
ion_dynamics = 'bfgs',
/
&CELL
cell_dynamics = 'bfgs',
cell_dofree = 'all',
press = 0.00000000,
/
ATOMIC_SPECIES
O 15.9994 O.pbe-n-kjpaw_psl.1.0.0.UPF
H 1.00794 H.pbe-kjpaw_psl.1.0.0.UPF
C 12.0107 C.pbe-n-kjpaw_psl.1.0.0.UPF
N 14.0067 N.pbe-n-kjpaw_psl.1.0.0.UPF
CELL_PARAMETERS angstrom
7.96880000 0.00000000 0.00000000
0.00000000 7.82400000 0.00000000
-1.05873327 0.00000000 12.21530422
ATOMIC_POSITIONS crystal
C 0.13736972 0.46722458 0.38443729 1 1 1
N 0.20244039 0.31752103 0.32198226 1 1 1
N 0.29362325 0.55928339 0.41167388 1 1 1
H 0.08202762 0.42863096 0.46232702 1 1 1
C 0.38339206 0.55981026 0.31270498 1 1 1
H 0.51189243 0.55507426 0.34255301 1 1 1
N 0.35284986 0.70176812 0.23904875 1 1 1
C -0.00170808 0.57676944 0.30700616 1 1 1
N -0.03738076 0.51121320 0.19509481 1 1 1
N 0.06881859 0.74719462 0.28238945 1 1 1
C 0.17893319 0.72178601 0.19370090 1 1 1
H 0.17324555 0.82790076 0.14061943 1 1 1
H -0.12148821 0.58857022 0.34781269 1 1 1
C 0.10818311 0.55137925 0.13437707 1 1 1
H 0.06637380 0.57991565 0.05136663 1 1 1
C 0.32589474 0.38919598 0.25099407 1 1 1
N 0.23537352 0.42022091 0.14234147 1 1 1
H 0.43373232 0.30718560 0.24363040 1 1 1
N 0.29918255 0.70230480 0.47816794 1 1 1
O 0.43389958 0.77841303 0.48332609 1 1 1
O 0.17927396 0.73285089 0.53071612 1 1 1
N 0.48201878 0.73369027 0.16558102 1 1 1
O 0.62357623 0.68018884 0.19573220 1 1 1
O 0.44455469 0.80932399 0.07506612 1 1 1
N -0.04242974 0.88520248 0.27937532 1 1 1
O -0.15208172 0.88052035 0.34605724 1 1 1
O -0.00377943 1.01041442 0.22707824 1 1 1
N -0.13903597 0.36414331 0.17309997 1 1 1
O -0.24553412 0.33226569 0.23874085 1 1 1
O -0.13637515 0.30399969 0.08444366 1 1 1
N 0.23185676 0.29373325 0.06321047 1 1 1
O 0.16675342 0.33394184 -0.02941709 1 1 1
O 0.29194446 0.14935904 0.08830686 1 1 1
N 0.25357277 0.16896321 0.38118263 1 1 1
O 0.18439486 0.13902818 0.46389325 1 1 1
O 0.35262114 0.07145014 0.34014560 1 1 1
C 0.86263028 -0.03277542 0.61556271 1 1 1
N 0.79755961 -0.18247897 0.67801774 1 1 1
N 0.70637675 0.05928339 0.58832612 1 1 1
H 0.91797238 -0.07136904 0.53767298 1 1 1
C 0.61660794 0.05981026 0.68729502 1 1 1
H 0.48810757 0.05507426 0.65744699 1 1 1
N 0.64715014 0.20176812 0.76095125 1 1 1
C 1.00170808 0.07676944 0.69299384 1 1 1
N 1.03738076 0.01121320 0.80490519 1 1 1
N 0.93118141 0.24719462 0.71761055 1 1 1
C 0.82106681 0.22178601 0.80629910 1 1 1
H 0.82675445 0.32790076 0.85938057 1 1 1
H 1.12148821 0.08857022 0.65218731 1 1 1
C 0.89181689 0.05137925 0.86562293 1 1 1
H 0.93362620 0.07991565 0.94863337 1 1 1
C 0.67410526 -0.11080402 0.74900593 1 1 1
N 0.76462648 -0.07977909 0.85765853 1 1 1
H 0.56626768 -0.19281440 0.75636960 1 1 1
N 0.70081745 0.20230480 0.52183206 1 1 1
O 0.56610042 0.27841303 0.51667391 1 1 1
O 0.82072604 0.23285089 0.46928388 1 1 1
N 0.51798122 0.23369027 0.83441898 1 1 1
O 0.37642377 0.18018884 0.80426780 1 1 1
O 0.55544531 0.30932399 0.92493388 1 1 1
N 1.04242974 0.38520248 0.72062468 1 1 1
O 1.15208172 0.38052035 0.65394276 1 1 1
O 1.00377943 0.51041442 0.77292176 1 1 1
N 1.13903597 -0.13585669 0.82690003 1 1 1
O 1.24553412 -0.16773431 0.76125915 1 1 1
O 1.13637515 -0.19600031 0.91555634 1 1 1
N 0.76814324 -0.20626675 0.93678953 1 1 1
O 0.83324658 -0.16605816 1.02941709 1 1 1
O 0.70805554 -0.35064096 0.91169314 1 1 1
N 0.74642723 -0.33103679 0.61881737 1 1 1
O 0.81560514 -0.36097182 0.53610675 1 1 1
O 0.64737886 -0.42854986 0.65985440 1 1 1
K_POINTS crystal
2
0.2500000 0.2500000 0.2500000 4
0.7500000 0.2500000 0.2500000 4
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