Dear readers,
I am using OpenMx 3.8 compiled with option -O2. The test runs showed that the compilation is successful with this flag. I am running a graphene system with 4 carbon atoms in a unit cell. In accordance with this unit cell, the Dirac point lies at P-point in reciprocal space. To do band calculations, if i use an E-cut of 250Ry (which i assume is already quite high) and grid size of (13 13 1) with C6-s2p1 PAO's, i get a band gap of about 0.001ev with cohesive energy 8.1ev. My question is why i am not getting a zero-band gap (-O2 flag was used for compilation) ? Please suggest
This is the input file that i am using for my calculations
#
File Name
#
System.CurrrentDirectory ./ # default=./
System.Name graphene
DATA.PATH ../../../../DFT_DATA13
level.of.stdout 1 # default=1 (1-3)
level.of.fileout 1 # default=1 (0-2)
#
Definition of Atomic Species
#
Species.Number 1
#
Atoms
#
Atoms.Number 4
Atoms.SpeciesAndCoordinates.Unit Ang # Ang|AU
Atoms.UnitVectors.Unit Ang # Ang|AU
#
SCF or Electronic System
#
scf.XcType GGA-PBE # LDA|LSDA-CA|LSDA-PW|GGA-PBE
scf.SpinPolarization on # On|Off|NC
scf.ElectronicTemperature 300.0 # default=300 (K)scf.energycutoff 250.0 # default=150 (Ry)
scf.maxIter 200 # default=40
scf.EigenvalueSolver Band # DC|GDC|Cluster|Band
scf.lapack.dste dstevx # dstegr|dstedc|dstevx, default=dstegr
scf.Kgrid 13 13 1 # means n1 x n2 x n3
scf.Mixing.Type rmm-diisk # Simple|Rmm-Diis|Gr-Pulay|Kerker|Rmm-Diisk
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.Mixing.History 5 # default=5
scf.Mixing.StartPulay 6 # default=6
scf.Mixing.EveryPulay 6 # default=6
scf.criterion 1.0e-10 # default=1.0e-6 (Hartree)
#
MD or Geometry Optimization
#
MD.Type Nomd # Opt|EF|BFGS|RF|DIIS
MD.Opt.DIIS.History 6 # default=3
MD.Opt.StartDIIS 7 # default=5
MD.Opt.EveryDIIS 6 # default=10
MD.maxIter 200 #
MD.Opt.criterion 1.0e-4 # default=1.0e-4 (a.u.)
#
Band dispersion
#
Band.dispersion on # on|off, default=off
if
#
Dos.fileout off # on|off, default=off
Dos.Erange -15.0 25.0 # default = -20 20
Dos.Kgrid 300 300 1 # default = Kgrid1 Kgrid2 Kgrid3
DosGauss.fileout off
DosGauss.Num.Mesh 4000
DosGauss.Width 0.01
Hi three,
There are two applications called OpenMx, this one, which is for structural modeling, and another for chemistry, which is the one you want :-)
Thanks for your reply. I am bit confused now. Can you please share link for both types of OpenMX.
Now, I got it. By mistake I wrote OpenMx, I actually meant OpenMX the one for chemistry. Thanks for clarification.
You want http://www.openmx-square.org/.
We are using this very OpenMX
Thanks I realized I am on wrong forum. :D