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weird and unreasonable total energies in Si-bulk geometry relaxation
Date: 2008/07/26 05:11
Name: Mauro   <mantegm@tcd.ie>

Dear Prof. Ozaki,

I made many calculations of bulk Silicon relaxation (only 2 atoms cell) using different basis sets (s32p31, s42p41, s52p51, s21p21d21, s32p32d21 etc...) and different basis cutoffs (6.0, 6.5, 7.0, 7.5), with and without the orbital optimization,
but I got very strange values of the total energy and the trend is, mostly using the orbital optimization, quite far from a parabola.
In many cases I got an oscillating trend with differences around 1 hartree!
Could you help me to solve the problem?
This is an example of an input file I used: (The total energy I got is around -7 Hartree, 1 hartree less than the value is supposed to be!)
Thanks a lot

Best regards

Mauro


#
# File Name
#

System.CurrrentDirectory ./ # default=./
System.Name Si-EF-s42p41-2.700
DATA.PATH /home/mantega/openmx3.4/DFT_DATA06/
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 1
<Definition.of.Atomic.Species
Si Si7.0-s42p41 Si_CA
Definition.of.Atomic.Species>

#
# Atoms
#

Atoms.Number 2
Atoms.SpeciesAndCoordinates.Unit FRAC # Ang|AU|FRAC
<Atoms.SpeciesAndCoordinates # Unit=Ang.
1 Si 0.0000 0.0000 0.0000 2.0 2.0
2 Si 0.2500 0.2500 0.2500 2.0 2.0
Atoms.SpeciesAndCoordinates>

Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors # unit=Ang.
0.000000 2.700 2.700
2.700 0.000000 2.700
2.700 2.700 0.000000
Atoms.UnitVectors>

#
# SCF or Electronic System
#

scf.XcType LDA # LDA|LSDA-CA|LSDA-PW
scf.SpinPolarization off # On|Off
scf.Hubbard.U off # On|Off
#scf.Hubbard.Occupation # onsite|full|dual
#Hubbard.U.value
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 150.0 # default=150 (Ry)
scf.maxIter 40 # default=40
scf.EigenvalueSolver band # Recursion|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 6 6 6 # means 4x4x4
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diisk|Gr-Pulay
scf.Init.Mixing.Weight 0.30 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.40 # default=0.40
scf.Kerker.factor 1.0 # default=1.0
scf.Mixing.History 6 # default=6
scf.Mixing.StartPulay 12 # default=6
scf.criterion 1.0e-6 # default=1.0e-6 (Hartree)

#
# 1D FFT
#

1DFFT.NumGridK 900 # default=900
1DFFT.NumGridR 900 # default=900
1DFFT.EnergyCutoff 3600.0 # default=3600 (Ry)

#
# Orbital Optimization
#

orbitalOpt.Method Restricted # Off|Unrestricted|Restricted
orbitalOpt.InitCoes Symmetrical # Symmetrical|Free
orbitalOpt.initPrefactor 0.1 # default=0.1
orbitalOpt.scf.maxIter 25 # default=12
orbitalOpt.MD.maxIter 10 # default=5
orbitalOpt.per.MDIter 5000 # default=1000000
orbitalOpt.criterion 1.0e-4 # default=1.0e-4 (Hartree/borh)^2

#
# output of contracted orbitals
#

CntOrb.fileout on # on|off, default=off
Num.CntOrb.Atoms 1 # default=1
<Atoms.Cont.Orbitals
1
Atoms.Cont.Orbitals>

#
# SCF Order-N
#

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

#
# MD or Geometry Optimization
#

MD.Type EF # Nomd|Opt|DIIS|BFGS||RF|EF|NVE|NVT_VS|NVT_NH
MD.Opt.DIIS.History 3 # default=3
MD.Opt.StartDIIS 5 # default=5
MD.maxIter 1 # default=1
MD.TimeStep 1.0 # default=0.5 (fs)
MD.Opt.criterion 1.0e-4 # default=1.0e-4 (Hartree/bohr) ~0.005 eV/A

#
# Band dispersion
#
# if <Band.KPath.UnitCell does not exist,
# the reciprical lattice vector is employed.

Band.dispersion off # on|off, default=off
Band.Nkpath 5
<Band.kpath #CDML setting
30 0.0 0.0 0.0 0.5 0.0 0.5 g X
30 0.5 0.0 0.5 0.5 0.25 0.75 X W
30 0.5 0.25 0.75 0.5 0.5 0.5 W L
30 0.5 0.5 0.5 0.0 0.0 0.0 L g
30 0.0 0.0 0.0 0.5 0.0 0.5 g X
Band.kpath>

#
# MO output
#

MO.fileout off # on|off
num.HOMOs 1 # default=1
num.LUMOs 1 # default=1
MO.Nkpoint 2 # default=1
<MO.kpoint
0.0 0.0 0.0
0.3 0.0 0.0
MO.kpoint>

#
# DOS and PDOS
#

Dos.fileout off # on|off, default=off
Dos.Erange -20.0 20.0 # default = -20 20
Dos.Kgrid 12 12 12 # default = Kgrid1 Kgrid2 Kgrid3

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