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Too violet variation of "Uele" value under Electric field calculation ?
Date: 2008/06/01 22:11
Name: Fuh Huei-Ru   <r95222073@ntu.edu.tw>

Dear Prof.Ozaki,
I am studying about silicon nanowire under Electric Field effect in openmx 3.3 edition. The procedure which I am doing now is to find out the most stable structure of SiNWs under electric field, and the following data are my input files:
The problem is the output data of gUeleh value which has a violet variation in the MD process. So I would like to ask how to improve the big variation value of gUeleh situation and correct my input file?
Thanks a lot !
Fuh Huei-Ru,
The Physics Department of National Taiwan University, Taiwan 106

#
# SCF or Electronic System
#

scf.XcType LDA # LDA|LSDA-CA|LSDA-PW
scf.SpinPolarization off # On|Off
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 130.0 # default=150 (Ry)
scf.maxIter 60 # default=40
scf.EigenvalueSolver band # Recursion|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 1 1 8 # means 4x4x4
scf.Mixing.Type RMM-DIISK # Simple|Rmm-Diis|Gr-Pulay
scf.Init.Mixing.Weight 0.010 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.20 # default=0.40
scf.Mixing.History 6 # default=5
scf.Mixing.StartPulay 8 # default=6
scf.criterion 1.0e-4 # default=1.0e-6 (Hartree)
scf.Electric.Field 1.0e-7 0.0 0.0 # default=0.0 0.0 0.0 (GV/m)

#
# 1D FFT
#

1DFFT.NumGridK 900 # default=900
1DFFT.NumGridR 900 # default=900
1DFFT.EnergyCutoff 3600.0 # default=3DFFT.EnergyCutoff*3.0 (Ry)

#
# Orbital Optimization
#

orbitalOpt.Method Off # Off|Unrestricted|Restricted
orbitalOpt.InitCoes Symmetrical # Symmetrical|Free
orbitalOpt.initPrefactor 0.1 # default=0.1
orbitalOpt.scf.maxIter 14 # default=12
orbitalOpt.MD.maxIter 5 # default=5
orbitalOpt.per.MDIter 4 # default=1000000
orbitalOpt.criterion 1.0e-5 # default=1.0e-4 (Hartree/borh)^2

#
# output of contracted orbitals
#

CntOrb.fileout off # on|off, default=off
Num.CntOrb.Atoms 4 # default=1
<Atoms.Cont.Orbitals
7
12
24
80
Atoms.Cont.Orbitals>

#
# SCF Order-N
#

orderN.HoppingRanges 8.389 # default=5.0 (Ang)
orderN.NumHoppings 2 # default=2
orderN.KrylovH.order 800 # default=400

#
# MD or Geometry Optimization
#

MD.Type EF # Nomd|Constant_Energy_MD|Opt
MD.Opt.DIIS.History 5
MD.Opt.StartDIIS 6 # default=5
MD.maxIter 4000 # default=1
MD.TimeStep 0.5 # default=0.5 (fs)
MD.Opt.criterion 1.0e-4 # default=1.0e-4 (Hartree/bohr)

The above input file cause a violet variation of the gUeleh value in the output file in the MD process as following.

***********************************************************
***********************************************************
SCF history at MD= 4
***********************************************************
***********************************************************

SCF= 1 NormRD= 1.000000000000 Uele= -94.537078474058
SCF= 2 NormRD= 6.937095570916 Uele= -515.286889806109
SCF= 3 NormRD= 6.837953751354 Uele= -515.512521395616
SCF= 4 NormRD= 6.911298117974 Uele= -515.942166325879
SCF= 5 NormRD= 6.892706382915 Uele= -515.849752460429
SCF= 6 NormRD= 5.644403479527 Uele= -532.729364097058
SCF= 7 NormRD= 9.534497932145 Uele= -433.634234705452
SCF= 8 NormRD= 9.103577900376 Uele= -438.661536600219
SCF= 9 NormRD= 6.315584550266 Uele= -496.460260020430
SCF= 10 NormRD= 3.243321384388 Uele= -542.253838222562
SCF= 11 NormRD= 2.482195374189 Uele= -547.247259811912
SCF= 12 NormRD= 9.499518865166 Uele= -560.457036563512
SCF= 13 NormRD= 9.471830735430 Uele= -548.172345777096
SCF= 14 NormRD= 10.763134859089 Uele= -513.650260216090
SCF= 15 NormRD= 6.347874849364 Uele= -549.567358095082
SCF= 16 NormRD= 4.410873043046 Uele= -532.600642481035
SCF= 17 NormRD= 3.676878608184 Uele= -548.782900810462
SCF= 18 NormRD= 1.686547562996 Uele= -572.479429034289
.
.
.
*******************************************************
Total energy (Hartree) at MD = 4
*******************************************************

Uele. -552.911918093020

Ukin. 250.310390125264
UH0. -2527.663616202190
UH1. 8.361467590510
Una. -164.399102268264
Unl. 96.818898223320
Uxc0. -37.395530290849
Uxc1. -37.395530290849
Ucore. 2349.830990051109
Uhub. 0.000000000000
Ucs. 0.000000000000
Uzs. 0.000000000000
Uzo. 0.000000000000
Uef. 0.000557915684
Utot. -61.531475146266
***********************************************************
***********************************************************
SCF history at MD= 5
***********************************************************
***********************************************************

SCF= 1 NormRD= 1.000000000000 Uele= -720.444799073374
SCF= 2 NormRD= 23.449243093184 Uele= -909.831408880318
SCF= 3 NormRD= 19.628525578075 Uele= -904.156462952078
SCF= 4 NormRD= 23.363826984184 Uele= -894.634727584993
SCF= 5 NormRD= 23.333829245058 Uele= -889.019756961735
SCF= 6 NormRD= 19.491439433749 Uele= -415.453535113369
SCF= 7 NormRD= 25.899943154665 Uele= -1855.381047909435
SCF= 8 NormRD= 25.714025129037 Uele= -1807.211506705366
SCF= 9 NormRD= 18.939784098888 Uele= -672.702801482023
SCF= 10 NormRD= 15.162883158666 Uele= -272.858472977573
SCF= 11 NormRD= 18.648285083938 Uele= -275.513253257958
SCF= 12 NormRD= 23.239749119369 Uele= -613.681031288880
SCF= 13 NormRD= 22.790044601202 Uele= -572.182562368118
SCF= 14 NormRD= 18.160386953865 Uele= -455.783957807431
SCF= 15 NormRD= 17.394994574680 Uele= -319.330974734747
SCF= 16 NormRD= 15.837872618638 Uele= -308.139633434623
SCF= 17 NormRD= 13.324745336305 Uele= -241.626271287086
SCF= 18 NormRD= 7.777641671185 Uele= -151.975475196172
.
.
.
*******************************************************
Total energy (Hartree) at MD = 5
*******************************************************

Uele. -92.733705260984

Ukin. 106.395945634065
UH0. -2549.243440142449
UH1. 0.313392115451
Una. -174.219092566574
Unl. 74.937888959029
Uxc0. -41.481805884726
Uxc1. -41.481805884726
Ucore. 2373.158602734037
Uhub. 0.000000000000
Ucs. 0.000000000000
Uzs. 0.000000000000
Uzo. 0.000000000000
Uef. -0.010430423199
Utot. -251.630745459093


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Re: Too violet variation of "Uele" value under Electric field calculation ? ( No.1 )
Date: 2008/06/11 11:53
Name: T.Ozaki

Hi,

Did you obtain the converged result when you perform the optimization
without electric field ?

I think that the SCF oscillation may not come from applying the electric field.
For example, you can find an example, H2O-EF.dat, in work/input_example.
In this case, the SCF iteration converges rapidly even if the electric field
is applied.

The oscillation may be suppressed by setting the following keywords:

scf.Kerker.factor 5.0
scf.Mixing.EveryPulay 1
scf.Mixing.History 30

Also, I noticed that you used

scf.criterion 1.0e-4

This is a too large criterion which can bring the oscillation in the geometry
optimization because of inaccuracy of caculated forces.

Of course, a set of proper parameters depends on system.
looking for the proper parameters may lead to saving computational time.

Best regards,

TO
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Re: Too violet variation of "Uele" value under Electric field calculation ? ( No.2 )
Date: 2008/06/12 20:20
Name: Huei-Ru Fuh  <r95222073@ntu.edu.tw>

Dear Prof. Ozaki,

Thank you very much for you help.

Huei-Ru Fuh
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