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Problem in Geometry Optimization
Date: 2017/10/22 18:41
Name: Reza   <reza_b_m_a@yahoo.com>

Dear Users,
I have prepared a 'DAT' file for Ni-doped graphene interacting with CO molecule in a slab form. You can see my input file here:
========
#
# File Name
#

System.CurrrentDirectory ./ # default=./
System.Name Graphene_Ni_BFGS
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 0 # default=1 (1-3)

#
# Definition of Atomic Species
#

Species.Number 3
<Definition.of.Atomic.Species
O O6.0-s2p2 O_PBE13
C C6.0-s2p2 C_PBE13
Ni Ni6.0H-s2p2d2 Ni_PBE13H
Definition.of.Atomic.Species>

#
# Atoms
#

Atoms.Number 20
Atoms.SpeciesAndCoordinates.Unit FRAC # Ang|AU
<Atoms.SpeciesAndCoordinates # Unit=Ang.
1 C -0.013296 -0.025347 0.000000 2 2
2 C -0.011724 0.308751 -0.004363 2 2
3 C -0.012404 0.641976 -0.005942 2 2
4 C 0.202677 0.072137 0.013274 2 2
5 C 0.205166 0.428206 0.002035 2 2
6 C 0.209618 0.754033 -0.005259 2 2
7 C 0.321167 -0.025348 0.000004 2 2
8 C 0.321549 0.644567 -0.003330 2 2
9 C 0.542929 0.085996 -0.003018 2 2
10 C 0.556257 0.428206 0.002036 2 2
11 C 0.544340 0.755463 -0.002816 2 2
12 C 0.654735 -0.023747 -0.004346 2 2
13 C 0.653691 0.308751 -0.004361 2 2
14 C 0.656235 0.644567 -0.003329 2 2
15 C 0.876286 0.085997 -0.003021 2 2
16 C 0.877213 0.421211 -0.007169 2 2
17 C 0.877632 0.754033 -0.005260 2 2
18 C 0.552276 0.771314 0.176691 2 2
19 Ni 0.325118 0.317023 0.057023 9 9
20 O 0.455314 0.577374 0.176691 3 3
Atoms.SpeciesAndCoordinates>
Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors # unit=Ang.
7.423110097 0.000125617 0.000000000
-3.711673032 6.455997625 0.000000000
0.000000000 0.000000000 20.71189019
Atoms.UnitVectors>

#
# SCF or Electronic System
#

scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW
scf.SpinPolarization off # On|Off
scf.ElectronicTemperature 2000.0 # default=300 (K)
scf.energycutoff 1000.0 # default=150 (Ry)
scf.maxIter 1700 # default=40
scf.EigenvalueSolver krylov # Recursion|Cluster|Band
scf.Kgrid 4 4 1 # means 4x4x4
scf.Mixing.Type gr-pulay # Simple|Rmm-Diis|Gr-Pulay
scf.Init.Mixing.Weight 0.20 # default=0.30
scf.Min.Mixing.Weight 0.01 # default=0.001
scf.Max.Mixing.Weight 0.300 # default=0.40
scf.Mixing.History 12 # default=5
scf.Mixing.StartPulay 12 # default=6
scf.criterion 1.0e-8 # default=1.0e-6 (Hartree)

#
# MD or Geometry Optimization
#

MD.Type EF # Nomd|Opt|DIIS|NVE|NVT_VS|NVT_NH
MD.Opt.DIIS.History 4 # default=7
MD.Opt.StartDIIS 3 # default=5
MD.Opt.EveryDIIS 500 # default=10
MD.maxIter 400 # default=1
MD.Opt.criterion 5.0e-4 # default=1.0e-4 (Hartree/bohr)
============================================
I have relaxed this structure with 0.001Ry/Bohr with Quantum-Espresso-6.1, and with 0.0257 eV/A with VASP5.4, and with FHI-aims2016V3.
I used PAW of PSlibrary 1.0 for QE (45/400Ry cutoff of PW), and 400 Ry for VASP, and tight for FHI-aims. All codes finished GO job during logical time. However, for OPENMX-3.8 (downloaded last week), the force reduces to 0.003 Ha/Ry but doesn't reduce anymore.
I tested different methods for GO, such as DIIS, EF, BFGS, but problem remains.
Due to the DZ basis set I have used, SCF is very fast, but GO is near to 0.003 after 12h.

I increased scf.energycutoff even till 1000Ry, and changing GO setting.
Any help
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Re: Problem in Geometry Optimization ( No.1 )
Date: 2017/10/23 23:44
Name: Reza  <reza_b_m_a@yahoo.com>

finally, I got the normal termination of openmx, but in 3 h.

SCF speed is very very high, but GO needs more steps comparing to other codes.
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Re: Problem in Geometry Optimization ( No.2 )
Date: 2017/10/26 19:48
Name: S. Nakamura  <nakamura.s.bh@m.titech.ac.jp>

Hi,

As I saw your input file, I suppose "scf.EigenvalueSolver Band" is better.
"krylov" method may be suitable, when your system is so large(more than 500 atoms).

I think your "scf.ElectronicTemperature" is also too high.
You can refer to
http://www.openmx-square.org/forum/patio.cgi?mode=view&no=1512

Besides, you should also try "MD.Type RF" .

Best regards,

S. Nakamura
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