Reason for why high precision gives wrong band gap.
Moderators: Global Moderator, Moderator
-
- Newbie
- Posts: 30
- Joined: Thu Apr 18, 2013 8:31 am
Reason for why high precision gives wrong band gap.
Dear sir,
I make my incar file for geometry optimisation of a one dimensional polymer like this:
SYSTEM=POLYMER
PREC=Normal
IBRION=2
EDIFF=1.0e-06
EDIFFG=1.0e-05
INIWAV=1
ISTART=0
ICHARG=2
After that I submit the job for band structure by using the CHGCAR CONTCAR file and perform a self-consistent run.
I get the almost correct value of band gap. but the dE value in OSZICAR file was gone only upto 0.392E-02 whereas I had given the value of EDIFFG 1E-05.
To correct this problem, I use the incar file with NSW=200 and ISMEAR=0 AND 1 respectively in two different jobs to see the results.
the value of dE goes to E-05. But the band gap is incorrect in both cases.
I am finding difficulty to understand the reason for this.
Please guide me.
I make my incar file for geometry optimisation of a one dimensional polymer like this:
SYSTEM=POLYMER
PREC=Normal
IBRION=2
EDIFF=1.0e-06
EDIFFG=1.0e-05
INIWAV=1
ISTART=0
ICHARG=2
After that I submit the job for band structure by using the CHGCAR CONTCAR file and perform a self-consistent run.
I get the almost correct value of band gap. but the dE value in OSZICAR file was gone only upto 0.392E-02 whereas I had given the value of EDIFFG 1E-05.
To correct this problem, I use the incar file with NSW=200 and ISMEAR=0 AND 1 respectively in two different jobs to see the results.
the value of dE goes to E-05. But the band gap is incorrect in both cases.
I am finding difficulty to understand the reason for this.
Please guide me.
Last edited by shyam on Sat Jun 01, 2013 9:30 am, edited 1 time in total.
-
- Global Moderator
- Posts: 1817
- Joined: Mon Nov 18, 2019 11:00 am
Re: Reason for why high precision gives wrong band gap.
Hi,
We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.
Best wishes,
VASP