Dear,
I have done some tests about graphite using VDW-DRSLL in
siesta-trunk-367.The input and initial structures comes from
trunk-367/Tests/graphite_vdw_df. I test three functional LDA,GGA and VDW.
However,their results are not very consistent with the experimental data.
For the calculated three interlayer equilibrium distance, LDA, GGA and VDW
are all smaller than the the experimental data 0.3354nm. The LDA result is even
smaller that 0.3100nm. The interlayer distance is 0.3250nm and 0.3225nm for GGA
and VDW,respectively.
What is the matter with my calculations?
SystemName Graphite
SystemLabel graphite
NumberOfAtoms 4
NumberOfSpecies 1
%block ChemicalSpeciesLabel
1 6 C.vdw
%endblock ChemicalSpeciesLabel
LatticeConstant 1 Ang
%block LatticeParameters
2.4610 2.4610 6.7080 90.0000 90.0000 120.0000
%endblock LatticeParameters
AtomicCoordinatesFormat NotScaledCartesianAng
%block AtomicCoordinatesAndAtomicSpecies
0.00000000 0.00000000 0.00000000 1 C 1
0.00000000 0.00000000 3.35400000 1 C 2
1.23050004 0.71042953 3.35400000 1 C 3
0.00000000 1.42085905 0.00000000 1 C 4
%endblock AtomicCoordinatesAndAtomicSpecies
XC_functional VDW
XC_authors DRSLL
%block PS.lmax
C.vdw 2
%endblock PS.lmax
