Top Page > Browsing
a bad relaxed structure from the RFC5 geometry optimizaiton
Date: 2018/06/04 17:24
Name: Jack

Dear all,

I am trying to use OpenMX to relax a simple system, TiO2 (the input file see below). The optimization algorithm is the OpenMX suggested RFC5. But after few relaxation steps, OpenMX generates a weird structure (-nan) and the electronic calculations cannot be converged.

******************************************************
MD or geometry opt. at MD = 9
*******************************************************

WWW1 tmp1=-0.114862131431 tmp2=-917592780013761956375895808328198843994265663672291382938734586330842634652457763864576.000000000000
<RF> |Maximum force| (Hartree/Bohr) =18.242384331415
<RF> Criterion (Hartree/Bohr) = 0.000100000000

Cell vectors and derivatives of total energy with respect to them
a1(Ang.) = -nan -nan -nan dE/da1(a.u.) = -2.56150 0.51899 -0.72357
a2(Ang.) = -nan -nan -nan dE/da2(a.u.) = 0.51899 -2.56150 -0.72357
a3(Ang.) = -nan -nan -nan dE/da3(a.u.) = -1.14096 -1.14096 -5.13335



TiO2 input OpenMX file is:

DATA.PATH /data/jack/soft/openmx3.8/DFT_DATA13
System.CurrrentDirectory ./ # default=./
System.Name om
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 1 # default=1 (1-3)

#
# restart using a restart file, *.rst
#

scf.restart off # on|off,default=off

#
# Definition of Atomic Species
#

Species.Number 2
<Definition.of.Atomic.Species
Ti Ti7.0-s2p2d1 Ti_PBE13
O O6.0-s2p2d1 O_PBE13
Definition.of.Atomic.Species>

#
# MD or Geometry Optimization
#

MD.Type RFC5 # Nomd|Opt|DIIS|NVE|NVT_VS|NVT_NH
MD.Opt.DIIS.History 3 # default=7
MD.Opt.StartDIIS 5 # default=5
MD.Opt.EveryDIIS 100000 # default=10
MD.maxIter 100 # default=1
MD.TimeStep 0.5 # default=0.5 (fs)
MD.Opt.criterion 1.0e-4 # default=1.0e-4 (Hartree/bohr)

#
# SCF or Electronic System
#

scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW
scf.SpinPolarization off # On|Off
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 150.0 # default=150 (Ry)
scf.maxIter 170 # default=40
scf.EigenvalueSolver band # Recursion|Cluster|Band
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 0.200 # default=0.40
scf.Mixing.History 6 # default=5
scf.Mixing.StartPulay 12 # default=6
scf.criterion 1.0e-9 # default=1.0e-6 (Hartree)
scf.system.charge 0.0 # default=0.0
scf.Kgrid 6 6 10

#
#Atoms
#

Atoms.Number 6
<Atoms.SpeciesAndCoordinates
1 Ti 0.0000000000000000 0.0000000000000000 0.0000000000000000 6.0 6.0
2 Ti 0.5000000000000000 0.5000000000000000 0.5000000000000000 6.0 6.0
3 O 0.3045041660932300 0.3045041660932300 -0.0000000000000000 3.0 3.0
4 O 0.6954958339067701 0.6954958339067701 0.0000000000000000 3.0 3.0
5 O 0.1954958339067700 0.8045041660932299 0.5000000000000000 3.0 3.0
6 O 0.8045041660932299 0.1954958339067700 0.5000000000000000 3.0 3.0
Atoms.SpeciesAndCoordinates>
Atoms.UnitVectors.Unit Ang
<Atoms.UnitVectors
4.6296885670066326 0.0000000000000000 0.0000000000000000
0.0000000000000000 4.6296885670066326 0.0000000000000000
0.0000000000000000 0.0000000000000000 2.9427426777121406
Atoms.UnitVectors>

Any suggestion is welcomed.
Thanks
Jack
メンテ
Page: [1]

Re: a bad relaxed structure from the RFC5 geometry optimizaiton ( No.1 )
Date: 2018/06/04 18:34
Name: Naoya Yamaguchi

Hi,

What is the value for the keyword "Atoms.SpeciesAndCoordinates.Unit"?
It doesn't appear in your input file. I think as the default is "Ang", this problem occured, and you should specify "FRAC" for it.

Regards,
Naoya Yamaguchi
メンテ
Re: a bad relaxed structure from the RFC5 geometry optimizaiton ( No.2 )
Date: 2018/06/05 09:18
Name: Jack

Dear Prof. Yamaguchi,

Thanks for pointing it out. The problem is solved.

Cheers
メンテ

Page: [1]

Thread Title (must) Move the thread to the top
Your Name (must)
E-Mail (must)
URL
Password (used in modification of the submitted text)
Comment (must)

   Save Cookie