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yangxuezhang

金虫 (正式写手)

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注册: 2012-09-01
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专业: 凝聚态物性I:结构、力学和

[求助] 关于siesta计算铁的结合能的问题

因为是新手，想从简单的问题算起，不过算过之后发现算出来的结合能比实验数字大了蛮多，实际是4.28左右，算出来是5.6左右，不知道问题出在哪，附上我的输入文件，希望高手指教一下
SystemName    bcc Fe ferro GGA # Descriptive name of the system
SystemLabel          Fe          # Short name for naming files

# Output options

WriteCoorXmol
WriteMullikenPop    1

# Species and atoms

NumberOfSpecies       1
NumberOfAtoms       1
%block ChemicalSpeciesLabel
  1  26  Fe
%endblock ChemicalSpeciesLabel

# Basis

PAO.EnergyShift    50 meV
PAO.BasisSize       DZP
%block PAO.Basis
  Fe  2
  0  2  P
  6. 0.
  2  2
  0. 0.
%endblock PAO.Basis

LatticeConstant    2.87 Ang

%block LatticeVectors
0.50000 0.500000  0.500000
0.50000  -0.500000  0.500000
0.50000 0.500000 -0.500000
%endblock LatticeVectors

KgridCutoff       15. Ang

%block BandLines
  1  0.00000 0.000000  0.000000  \Gamma
40  2.00000 0.000000  0.000000  H
28  1.00000 1.000000  0.000000  N
28  0.00000 0.000000  0.000000  \Gamma
34  1.00000 1.000000  1.000000  P
%endblock BandLines

xc.functional       GGA          # Exchange-correlation functional
xc.authors          PBE          # Exchange-correlation version

SpinPolarized       true       # Logical parameters are: yes or no

MeshCutoff          150. Ry       # Mesh cutoff. real space mesh

# SCF options
MaxSCFIterations    40          # Maximum number of SCF iter
DM.MixingWeight    0.1          # New DM amount for next SCF cycle
DM.Tolerance       1.d-3       # Tolerance in maximum difference
                                 # between input and output DM
DM.UseSaveDM       true       # to use continuation files
DM.NumberPulay       3

SolutionMethod       diagon       # OrderN or Diagon
ElectronicTemperature  25 meV    # Temp. for Fermi smearing

# MD options

MD.TypeOfRun          cg          # Type of dynamics:
MD.NumCGsteps          0          # Number of CG steps for
                                 # coordinate optimization
MD.MaxCGDispl       0.1 Ang    # Maximum atomic displacement
                                 # in one CG step (Bohr)
MD.MaxForceTol       0.04 eV/Ang  # Tolerance in the maximum
                                 # atomic force (Ry/Bohr)

# Atomic coordinates
AtomicCoordinatesFormat    Fractional
%block AtomicCoordinatesAndAtomicSpecies
  0.000000000000 0.000000000000 0.000000000000  1
%endblock AtomicCoordinatesAndAtomicSpecies
然后把晶格常数改成10A，算出单个原子的能量，当然晶格常数我取了很多的点2.85.2.88之类的

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