core level shifts and average electrostatic potential at each ion

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Jiaye Li · #1 Post by **Jiaye Li** » Fri Oct 17, 2008 9:13 am

Dear All

I feel confused about the online manual of LVTOT-tag:
http://cms.mpi.univie.ac.at/vasp/vasp/node145.html

For example, I want to calculate a surface model, if I want to determine the average electrostatic potential of a ion, which file is needed to read the value?

If I want to obtain the core level shift, should I calculate the surface twice (neutral and positively charged(+1))? and then calculate it via the second equation as shown in the above link?

Thanks in advance

#2 Post by **admin** » Mon Oct 20, 2008 11:15 am

LVTOT generates a file (LOCPOT) in CHGCAR format (i.e. the potential on a 3d grid in the cell). In the default version of VASP, the XC-contribution to V is not included in these data, unless the appropriate line in main.F is commented. One can then generate planar averages of the potential by using the vtotav tool.

To obtain the corelevelshift, please simply do 2 runs (ICORELEVEL=1, ICORELEVEL=2 CLN,CLL,CLNT and CLZ have to be defined appropriately for the second run). The second run shifts the specified core electron to the far conduction band (to keep charge neutrality), therefore will not have to do a run with a positively charged cell. Please note however that corelevelshifts are not supported officially for vasp.4.6, on some machines/for some structures it gives errors
(it will be fully supported for vasp.5.1)

Jiaye Li · #3 Post by **Jiaye Li** » Wed Oct 22, 2008 1:57 am

Thanks