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Silver bulk modulus
Date: 2010/03/15 03:43
Name: B.Martins   <bmartins@ifi.unicamp.br>

Dear OpenMX users,

I am having some troubles with the bulk modulus calculation for Silver. I made a sequence of 9 lattice parameters and found the following total energies:

a(ANG) Et(Hartree)

3.086 -442.895
3.586 -442.794
3.786 -445.009
4.086 -445.125
4.096 -445.126
4.286 -445.133
5.086 -445.019
5.586 -444.940
6.086 -444.880

The curve has the right shape but the minimum is around 4.2 ang and not 4.09 which is the right value. I am sending one of the input files bellow.

#
# SCF calculation of a graphite sheet by the LDA
# and the band method
#

#
# File Name
#
System.CurrrentDirectory ./ # default=./
System.Name silver_bulk_8.0
DATA.PATH ../DFT_DATA
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 1 # default=1 (0-2)

#
# Definition of Atomic Species
#

Species.Number 1
<Definition.of.Atomic.Species
Ag Ag8.0-s1p1d1 Ag_CA
Definition.of.Atomic.Species>

#
# Atoms
#

Atoms.Number 4
Atoms.SpeciesAndCoordinates.Unit FRAC # Ang|AU
<Atoms.SpeciesAndCoordinates # Unit=Ang.
1 Ag 0.000000 0.000000 0.000000 8.5 8.5
2 Ag 0.000000 0.500000 0.500000 8.5 8.5
3 Ag 0.500000 0.000000 0.500000 8.5 8.5
4 Ag 0.500000 0.500000 0.000000 8.5 8.5
Atoms.SpeciesAndCoordinates>

Atoms.UnitVectors.Unit Ang # Ang|AU
<Atoms.UnitVectors # unit=Ang.
4.08570000000000 0.00000000000000 0.00000000000000
0.00000000000000 4.08570000000000 0.00000000000000
0.00000000000000 0.00000000000000 4.08570000000000
Atoms.UnitVectors>

#
# SCF or Electronic System
#

scf.XcType LDA # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization Off # On|Off|NC
scf.partialCoreCorrection Off # On|Off
scf.ElectronicTemperature 300.0 # default=300 (K)
scf.energycutoff 150.0 # default=150 (Ry)
scf.maxIter 500 # default=40
scf.EigenvalueSolver Band # DC|GDC|Cluster|Band
scf.Kgrid 8 8 8 # means 4x4x4
scf.Mixing.Type Rmm-Diisk # Simple|Rmm-Diis|Gr-Pulay|Kerker|Rmm-Diisk
scf.Init.Mixing.Weight 0.300 # default=0.30
scf.Min.Mixing.Weight 0.001 # default=0.001
scf.Max.Mixing.Weight 0.400 # default=0.40
scf.Mixing.History 7 # default=5
scf.Mixing.StartPulay 20 # default=6
scf.Mixing.EveryPulay 6 # default=6
scf.criterion 1.0e-6 # default=1.0e-6 (Hartree)
scf.lapack.dste dstevx # dstevx|dstedc|dstegr,default=dstevx
scf.Ngrid 32 32 32
scf.fixed.grid 0.0 0.0 0.0
#
# 1D FFT
#

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

#
# Orbital Optimization
#

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

#
# output of contracted orbitals
#

CntOrb.fileout off # 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

#
# MD or Geometry Optimization
#

MD.Type Nomd # Nomd|Opt|NVE|NVT_VS|NVT_NH
MD.maxIter 1 # default=1
MD.TimeStep 0.5 # default=0.5 (fs)
MD.Opt.criterion 1.0e-4 # default=1.0e-4 (Hartree/bohr)

#
# MO output
#

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

#
# DOS and PDOS
#

Dos.fileout on # on|off, default=off
Dos.Erange -20.0 20.0 # default = -20 20
Dos.Kgrid 10 10 5 # default = Kgrid1 Kgrid2 Kgrid3

#HS.Fileout on


I tried this in more than one machine and with different compilers to eliminate any compilation problems but the result was always the same. Does anyone had this kind of problem?

Regards,

B.Martins.
e
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