Siesterers
I'm modelling the cyanogen molecule, to check my pseudopotentials for C
and N in the molecule by seeing if a CG run gives the same equilibrium
bond lengths as experiment (from the NIST site).
The simulation converges after about 10 iterations and gives the right
sort of bond lengths. However, initially in the expansion there is a large
expansion of the N molecules. I'm only sampling over the gamma point
(should be good enough for small molecules) but cant figure why the
initial expansion.
Any ideas?
Thanks
Ian Shuttleworth
*********************************************************************
SystemName c2n2
SystemLabel c2n2
NumberOfAtoms 4
NumberOfSpecies 2
%block ChemicalSpeciesLabel
1 6 C # Species index, atomic number, species label
2 7 N # Species index, atomic number, species label
%endblock ChemicalSpeciesLabel
PAO.BasisSize STANDARD
PAO.EnergyShift 300 meV
PAO.BasisType split
%block Ps.lmax
C 3
N 3
%endblock Ps.lmax
#kgrid_cutoff = brillouin zone sampling paramter (>0 for >gamma point)
#kgrid_cutoff 20.0 Ang
#MeshCutoff = equivalent plane wave cut-off for grid
MeshCutoff 200 Ry
MaxSCFIterations 50
DM.MixingWeight 0.3
DM.NumberPulay 4
DM.Tolerance 1.d-3
DM.UseSaveDM
SolutionMethod diagon
ElectronicTemperature 25 meV
HarrisFunctional T
WriteCoorStep .true.
WriteForces .true.
WriteMDHistory .true.
MD.TypeOfRun cg
MD.NumCGsteps 100
MD.MaxCGDispl 0.1 Ang
MD.MaxForceTol 0.04 eV/Ang
#AtomicCoordinatesOrigin block is in Bohr
#1 Bohr = 0.52918 angstroem
%block AtomicCoordinatesOrigin
5.6691 1.8897 1.8897
%endblock AtomicCoordinatesOrigin
LatticeConstant 1.00 Ang
%block LatticeVectors
6.000 0.000 0.000
0.000 2.000 0.000
0.000 0.000 2.000
%endblock LatticeVectors
AtomicCoordinatesFormat ScaledCartesian
%block AtomicCoordinatesAndAtomicSpecies
-1.845 0 0 2
-0.695 0 0 1
0.695 0 0 1
1.845 0 0 2
%endblock AtomicCoordinatesAndAtomicSpecies
******************************************************************
Input file for C pseudopotential:
pg C
tm2 2.0
n=C c=car
0.0 0.0 0.0 0.0 0.0 0.0
1 4
2 0 2.00 0.00
2 1 2.00 0.00
3 2 0.00 0.00
4 3 0.00 0.00
1.25 1.25 1.25 1.25 0.00 0.00
******************************************************************
Input file for N pseudopotential:
pg N
tm2 2.0
n=N c=car
0.0 0.0 0.0 0.0 0.0 0.0
1 4
2 0 2.00 0.00
2 1 3.00 0.00
3 2 0.00 0.00
4 3 0.00 0.00
1.25 1.25 1.25 1.25 0.00 0.00
