why CHG file changes when I set ICHARG=11
Posted: Tue May 17, 2005 1:31 pm
Dear all,
I am doing optic calculations of carbon nanotubes. And my process is that:
1. doing a scf calculation with the following INCAR:
EDIFF=1E-6
ISMEAR= 0
SIGMA=0.05
ENCUT=450
2. read the old CHGCAR and WAVECAR and do a optic calculation without
scf, the new INCAR is:
ICHARG=11
EDIFF=1E-6
ISMEAR= 0
SIGMA=0.05
ENCUT=450
LOPTICS=.TRUE.
NPAR=1
Then I get a OPTIC file which contain the optic moment matrix.
However, I find that the CHG and CHGCAR file is rewritten and changed.
I diff the old and new CHG or CHGCAR files, and find something has been changed in these files.
Since I have set ICHARG=11, the charge density should not be changed.
The same thing happens when I calculate a Nb9 cluster.
However, for the system of GaAs and BaTiO3, the contents of CHG and CHGCAR do not change(although they also have been rewritten).
Is it because that I do not get a fine converged charge density of nanotube or cluster? But, I tested it in the GaAs, even for a not converged charge density, the CHG and CHGCAR files should not be changed when set ICHARG=11.
And then I am confused :-(
Thank you for your reading and hope you can give me some suggestions.
Best wishes.
jian
I am doing optic calculations of carbon nanotubes. And my process is that:
1. doing a scf calculation with the following INCAR:
EDIFF=1E-6
ISMEAR= 0
SIGMA=0.05
ENCUT=450
2. read the old CHGCAR and WAVECAR and do a optic calculation without
scf, the new INCAR is:
ICHARG=11
EDIFF=1E-6
ISMEAR= 0
SIGMA=0.05
ENCUT=450
LOPTICS=.TRUE.
NPAR=1
Then I get a OPTIC file which contain the optic moment matrix.
However, I find that the CHG and CHGCAR file is rewritten and changed.
I diff the old and new CHG or CHGCAR files, and find something has been changed in these files.
Since I have set ICHARG=11, the charge density should not be changed.
The same thing happens when I calculate a Nb9 cluster.
However, for the system of GaAs and BaTiO3, the contents of CHG and CHGCAR do not change(although they also have been rewritten).
Is it because that I do not get a fine converged charge density of nanotube or cluster? But, I tested it in the GaAs, even for a not converged charge density, the CHG and CHGCAR files should not be changed when set ICHARG=11.
And then I am confused :-(
Thank you for your reading and hope you can give me some suggestions.
Best wishes.
jian