[Pw_forum] structural relaxation for a M-M-M system
Sen
asen at iitk.ac.in
Sat Jun 9 11:21:11 CEST 2007
Dear all,
After a lot of trials, I am, however, not yet successful in
optimizing a metal-molecule-metal system as the forces are coming
like this:
.........
Total force = 0.095460 Total SCF correction = 0.000604
Total force = 0.082488 Total SCF correction = 0.000306
Total force = 0.046922 Total SCF correction = 0.000911
Total force = 0.056506 Total SCF correction = 0.000344
Total force = 0.054621 Total SCF correction = 0.000626
Total force = 0.065249 Total SCF correction = 0.000466
Total force = 0.083905 Total SCF correction = 0.000689
Total force = 0.079088 Total SCF correction = 0.000242
Total force = 0.062822 Total SCF correction = 0.000331
Total force = 0.042837 Total SCF correction = 0.000466
Total force = 0.043863 Total SCF correction = 0.000608
Total force = 0.060127 Total SCF correction = 0.000548
Total force = 0.056791 Total SCF correction = 0.000600
Total force = 0.055846 Total SCF correction = 0.000490
Total force = 0.048528 Total SCF correction = 0.000801
Total force = 0.035071 Total SCF correction = 0.000413
Total force = 0.032172 Total SCF correction = 0.000433
Total force = 0.039041 Total SCF correction = 0.000416
Total force = 0.044582 Total SCF correction = 0.000545
Total force = 0.046444 Total SCF correction = 0.000524
Total force = 0.054854 Total SCF correction = 0.000818
Total force = 0.063710 Total SCF correction = 0.000484
Total force = 0.062717 Total SCF correction = 0.000626
Total force = 0.065163 Total SCF correction = 0.000812
Total force = 0.075249 Total SCF correction = 0.001036
Total force = 0.088846 Total SCF correction = 0.000643
Total force = 0.105373 Total SCF correction = 0.000338
Total force = 0.120634 Total SCF correction = 0.000572
Total force = 0.126982 Total SCF correction = 0.000283
Total force = 0.113945 Total SCF correction = 0.000450
Total force = 0.108384 Total SCF correction = 0.000297
Total force = 0.099096 Total SCF correction = 0.000580
Total force = 0.077881 Total SCF correction = 0.000668
Total force = 0.095374 Total SCF correction = 0.000452
while the stress is the following:
total stress (Ry/bohr**3) (kbar) P=
34.70
total stress (Ry/bohr**3) (kbar) P=
34.72
total stress (Ry/bohr**3) (kbar) P=
35.27
total stress (Ry/bohr**3) (kbar) P=
35.66
total stress (Ry/bohr**3) (kbar) P=
35.07
total stress (Ry/bohr**3) (kbar) P=
33.99
total stress (Ry/bohr**3) (kbar) P=
32.67
total stress (Ry/bohr**3) (kbar) P=
31.43
total stress (Ry/bohr**3) (kbar) P=
31.16
total stress (Ry/bohr**3) (kbar) P=
31.69
total stress (Ry/bohr**3) (kbar) P=
32.41
total stress (Ry/bohr**3) (kbar) P=
33.54
total stress (Ry/bohr**3) (kbar) P=
33.84
total stress (Ry/bohr**3) (kbar) P=
34.53
total stress (Ry/bohr**3) (kbar) P=
34.35
total stress (Ry/bohr**3) (kbar) P=
34.06
total stress (Ry/bohr**3) (kbar) P=
33.97
total stress (Ry/bohr**3) (kbar) P=
34.12
total stress (Ry/bohr**3) (kbar) P=
34.65
total stress (Ry/bohr**3) (kbar) P=
34.86
total stress (Ry/bohr**3) (kbar) P=
34.38
total stress (Ry/bohr**3) (kbar) P=
33.60
total stress (Ry/bohr**3) (kbar) P=
32.83
total stress (Ry/bohr**3) (kbar) P=
32.23
total stress (Ry/bohr**3) (kbar) P=
32.38
total stress (Ry/bohr**3) (kbar) P=
32.16
total stress (Ry/bohr**3) (kbar) P=
32.24
total stress (Ry/bohr**3) (kbar) P=
32.34
total stress (Ry/bohr**3) (kbar) P=
32.88
total stress (Ry/bohr**3) (kbar) P=
34.00
total stress (Ry/bohr**3) (kbar) P=
33.58
total stress (Ry/bohr**3) (kbar) P=
33.10
total stress (Ry/bohr**3) (kbar) P=
32.30
total stress (Ry/bohr**3) (kbar) P=
31.50
I start my calculations with the following input file:
&CONTROL
calculation = "relax",
tstress = .TRUE.,
tprnfor = .TRUE.,
dt= 20,
outdir = "/work1/tmp",
prefix = "6r_md",
pseudo_dir = "/work1/pwscf/newwork1/pseudo",
/
&SYSTEM
nosym = .TRUE.,
ibrav = 6,
celldm(1) = 16.0,
celldm(3) = 6.7,
nat = 108,
ntyp = 4,
ecutwfc = 25.0,
ecutrho = 200.0 ,
occupations = "smearing",
degauss = 0.01,
smearing = "gauss",
/
&ELECTRONS
conv_thr = 1.e-7,
mixing_beta = 0.1,
/
&IONS
ion_dynamics = "damp",
pot_extrapolation = "second_order",
wfc_extrapolation = "second_order",
ATOMIC_SPECIES
Au 1.00 Au.pbe-van_ak.UPF
S 1.00 S.pbe-van_ak.UPF
C 1.00 C.pbe-van_ak.UPF
H 1.00 H.pbe-van_ak.UPF
ATOMIC_POSITIONS {bohr}
Au 0.000000000 -4.965200000 0.000000000 0 0 0
Au -4.319724000 -2.482600000 0.000000000 0 0 0
Au -4.319724000 2.482600000 0.000000000 0 0 0
.................
Au -2.774561616 0.031062380 28.596765964 1 1 1
Au 0.041848351 -0.082778583 32.636501628 1 1 1
Au -0.028301935 1.263362498 37.301572656 1 1 1
.................
C 0.003014820 -0.792207427 45.903314488 1 1 1
H -1.656592433 -2.071574048 45.925688702 1 1 1
H 1.659769150 -2.074993963 45.925343414 1 1 1
.................
Au 0.002439106 5.120271920 81.897457381 1 1 1
Au -4.361967945 2.134818447 81.462315449 1 1 1
Au -5.204105949 -3.027358489 81.522909929 1 1 1
.................
Au -4.319724000 2.482600000 98.968460000 0 0 0
Au -4.319724000 -2.482600000 98.968460000 0 0 0
Au 0.000000000 -4.965200000 98.968460000 0 0 0
K_POINTS {Gamma}
I tried with vc-relax as well but could not improve it much. In another
system, I came across the following forces:
Total force = 0.506859 Total SCF correction = 0.000423
Total force = 0.501602 Total SCF correction = 0.000666
Total force = 0.504022 Total SCF correction = 0.000468
Total force = 0.515807 Total SCF correction = 0.000445
Total force = 0.531093 Total SCF correction = 0.000497
Total force = 0.546169 Total SCF correction = 0.000294
Total force = 0.565997 Total SCF correction = 0.000298
Total force = 0.594369 Total SCF correction = 0.000437
Total force = 0.628540 Total SCF correction = 0.000323
Total force = 0.652224 Total SCF correction = 0.000388
Total force = 0.636638 Total SCF correction = 0.000299
Total force = 0.558604 Total SCF correction = 0.000572
Total force = 0.441045 Total SCF correction = 0.000310
Total force = 0.331614 Total SCF correction = 0.000424
Total force = 0.230756 Total SCF correction = 0.000319
Total force = 0.188110 Total SCF correction = 0.000422
Total force = 0.160244 Total SCF correction = 0.000236
Total force = 0.145254 Total SCF correction = 0.000270
Total force = 0.139637 Total SCF correction = 0.000262
Total force = 0.125084 Total SCF correction = 0.000424
Total force = 0.150679 Total SCF correction = 0.000854
Total force = 0.167059 Total SCF correction = 0.000294
Total force = 0.172462 Total SCF correction = 0.000478
Total force = 0.179529 Total SCF correction = 0.000434
Total force = 0.187906 Total SCF correction = 0.000499
Total force = 0.191868 Total SCF correction = 0.000428
Total force = 0.188061 Total SCF correction = 0.000504
Total force = 0.175147 Total SCF correction = 0.000272
Total force = 0.159927 Total SCF correction = 0.000273
Total force = 0.161611 Total SCF correction = 0.000373
Total force = 0.208462 Total SCF correction = 0.000460
Total force = 0.280821 Total SCF correction = 0.000192
Total force = 0.353126 Total SCF correction = 0.000699
Total force = 0.420761 Total SCF correction = 0.000602
Total force = 0.486584 Total SCF correction = 0.000230
Total force = 0.550967 Total SCF correction = 0.000360
Total force = 0.606887 Total SCF correction = 0.000672
Total force = 0.640920 Total SCF correction = 0.000602
Total force = 0.632764 Total SCF correction = 0.000467
Total force = 0.559615 Total SCF correction = 0.000506
Total force = 0.526823 Total SCF correction = 0.000464
Total force = 0.503575 Total SCF correction = 0.000432
.........
Could you please suggest me as to how I could get the "Total force"
something like 0.001 or of that sort?
Best regards,
Sen
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