dears:
i 'm trying use the seista to calculate the optical properties of
monolayer graphene and facing some problems,i wonder if somebody of you can
help me,thanks very much.
first:the files i need just *.psf and filename.fdf.and my fdf file is
listed as follows:
###############
SystemName Graphene optical
SystemLabel Graphene-optical
NumberOfAtoms 2
NumberOfSpecies 1
%block ChemicalSpeciesLabel
1 6 C
%endblock ChemicalSpeciesLabel
%block PAO.BasisSizes
C DZP
%endblock PAO.BasisSizes
PAO.EnergyShift 250 meV
LatticeConstant 2.46 Ang
%block LatticeVectors
0.866 0.500 0.000
0.866 -0.500 0.500
0.000 0.000 10.000
%endblock LatticeVectors
%block kgrid_Monkhorst_Pack
200 0 0 0.
0 200 0 0.
0 0 1 0.
%endblock kgrid_Monkhorst_Pack
MeshCutoff 200.0 Ry
MaxSCFIterations 50
DM.MixingWeight 0.3
DM.NumberPulay 3
DM.Tolerance 1.d-4
DM.UseSaveDM .true.
SolutionMethod diagon
ElectronicTemperature 25 meV
MD.TypeOfRun Verlet
MD.NumCGsteps 0
MD.MaxCGDispl 0.1 Ang
MD.MaxForceTol 0.04 eV/Ang
AtomicCoordinatesFormat ScaledCartesian
%block AtomicCoordinatesAndAtomicSpecies
0.000 0.000 0.000 1
1.42 0.000 0.000 1
%endblock AtomicCoordinatesAndAtomicSpecies
OpticalCalculation .true.
%block Optical.Mesh
20 20 20
%endblock Optical.Mesh
Optical.OffsetMesh .true.
Optical.PolarizationType polarized
%block Optical.Vector
1.0 0.0 0.0
%endblock Optical.Vector
Optical.Broaden 0.2 eV
Optical.EnergyMaximum 20.0 eV
Optical.EnergyMinimum 0.0 eV
################
i was used the command:siesta parallel 4<filename.fdf>filename.out &
it could export the file:SystemLable.EPSIMG,the energy range in this outfile is
correct,and then i used the command :
"/opt/siesta-3.0-rc2/bin/input <filename.EPSIMG "
to get the dielectric of the material,but it will come to a suggestion which
said:"Fsum rule is not fulfilled by more than a 20%,The dielectric function
will be extended to higher energies by enforcing the Fsum rule.This will
increase the quality of the quantities calculated via the Kramers-Kroning
relation".i just want to know whether it has influense on my results,and how to
handle this problems.
second: i get some informations from graphene papers which said the
conductivity and refraction index of graphene also have real part and imginary
part ,i used the siesta ca get the outfile.conductivity,but i don't know what
it represents,real part or imaginary part or some other datas?
thank you very much!!
