Everything about corelevels
Posted: Fri Jun 20, 2014 8:50 am
Dear VASP user community,
After several trials with VASP 5.3.3 and reviewing some of the Q&A it seems like there are still many people with questions about the CORELEVEL "1" and "2" calculations. I respect the VASP creators' decision not to "support" this option, which - if I understood correctly from the forum responses - means that no official "CORELEVEL cookbook" will be created, but this function has been made available as best as they can and the users will have to figure out how it works and when to use it themselves.
Here's my first question, although others will follow. I've read that for both CORELEVEL=1 and CORELEVEL=2 the energy associated to excitation (by all means correct me when I misspeak) can be determined by calculating "TOTEN" for a reference molecule (I suppose you have to launch the SAME calculation WITHOUT the core level instruction?) and then substracting the TOTEN of the CORELEVEL calculation. For example, THREAD 3525 and 9542 speak about this method. Beside the fact that I obtain very strange values doing that, it also seems strange for the CORELEVEL=1 option to work like this: CORELEVEL=1 calculates excitations on all atoms and if you ask me, that should yield many different TOTEN values (after all excitations from different atoms should have different energies associated to them), but after my iterative procedure I obtain only ONE TOTEN.
So... Isn't the core level simply calculated by using the energies after the phrase "the core state eigenenergies are"? Doesn't that make more sense?
After several trials with VASP 5.3.3 and reviewing some of the Q&A it seems like there are still many people with questions about the CORELEVEL "1" and "2" calculations. I respect the VASP creators' decision not to "support" this option, which - if I understood correctly from the forum responses - means that no official "CORELEVEL cookbook" will be created, but this function has been made available as best as they can and the users will have to figure out how it works and when to use it themselves.
Here's my first question, although others will follow. I've read that for both CORELEVEL=1 and CORELEVEL=2 the energy associated to excitation (by all means correct me when I misspeak) can be determined by calculating "TOTEN" for a reference molecule (I suppose you have to launch the SAME calculation WITHOUT the core level instruction?) and then substracting the TOTEN of the CORELEVEL calculation. For example, THREAD 3525 and 9542 speak about this method. Beside the fact that I obtain very strange values doing that, it also seems strange for the CORELEVEL=1 option to work like this: CORELEVEL=1 calculates excitations on all atoms and if you ask me, that should yield many different TOTEN values (after all excitations from different atoms should have different energies associated to them), but after my iterative procedure I obtain only ONE TOTEN.
So... Isn't the core level simply calculated by using the energies after the phrase "the core state eigenenergies are"? Doesn't that make more sense?