core level shift calculation

[yuxiao_zihan]

Dear VASP users,

Recently I did a calculation of core level with VASP4.6, I can not make sure it is right or not, since the final state is more stable than the one of initial state.
I did the calculation as following,
Two separate calculation with ICORELEVEL=1 or 2 for initial and final state respectively.
with ICORELEVEL=2, I switch to Z+1 approximation, and set
CLNT = 5
CLN = 2
CLL = 1
CLZ = 1
for Fe 2p orbital.

As I understand, the tot energy difference is the energy needed to excite an electron. However, here the tot energy of the final state is more stable than the initial one. I am puzzled for long time. Did I made some serious mistake?

Thank you very much.

Best wishes

[admin]

what do you mean by "Z+1-approximation"?
[ Edited Tue Feb 17 2009, 12:09PM ]

[yuxiao_zihan]

Dear admin,
I think there are two ways to calculate the core level,
One way is to generate a new pseudopotential, similar to Kohler and Kresse's PRB_2004.
The other way is to use another pseudopotential (the one next to the atom, in this case is Co instead of Fe) to simulate the final state. This is what I am doing. Did I misunderstand it?

Thank you again,
Best wishes,

[admin]

sorry, if you use a PP with one more valence electron, this does of course not correspond to the shift of a core electron into the CB. you have to follow the approach described in the paper of Köhler and Kresse to calculate CLS