Energy of a charged bulk system
Posted: Thu Mar 16, 2006 11:07 am
Hi,
I am interested in calculating the bulk energy of an oxide (ABO3-type) with a O2- vacancy. To do that, I removed one oxygen atom from the supercell (cubic), and further reduced the total electrons by 2 to make the system +2 charged. I find that the total energy is less (by almost 16eV) than the system with neutral vacancy --all the parameters were kept same.
Obviously, this cannot be correct -- what is going wrong? Do I need to add the dipole correction for the charged system separately. If yes, what flags, needs to be set for the bulk (manual says that IDIPOL=1-3 is for slab and 4 for atoms/molecules)?
Regards
MC
I am interested in calculating the bulk energy of an oxide (ABO3-type) with a O2- vacancy. To do that, I removed one oxygen atom from the supercell (cubic), and further reduced the total electrons by 2 to make the system +2 charged. I find that the total energy is less (by almost 16eV) than the system with neutral vacancy --all the parameters were kept same.
Obviously, this cannot be correct -- what is going wrong? Do I need to add the dipole correction for the charged system separately. If yes, what flags, needs to be set for the bulk (manual says that IDIPOL=1-3 is for slab and 4 for atoms/molecules)?
Regards
MC