Gao, If you already have your O2 molecule in a box big enough so that it is already isolated from its periodic images (10, 12 Ang should do the job), there is no need to place the O2 molecule far from the surface, and all you need is the isolated O2 molecule calculation and the O2+surface calculation. What you want to do is the following:
1) Shift the pdos for the isolated O2 molecule's 2p orbitals by the Fermi level of this calculation. 2) Shift the pdos for the O2 molecule + surface calculation by the Fermi level of the O2+surface calculation. 3) Put them in the same graph. Marcos On Wed, Feb 23, 2011 at 12:40 PM, Fen Hong <[email protected]> wrote: > Dear all > I am confused by the fermi level recently. > I want to compare how the O2 2p orbital changes after it adsorbed on > graphite surface. > I compute the O2 and O2-surface , get fermi level separately, Ef_O2, and > Ef_O2-surface. > then I get O2 2p orbital by pdosxml, shift the two 2p orbital energy to > zero by subtracting Ef_O2, Ef_O2-surface, > And plot them in one coordinate system. Is it correct? > Or we can put the O2 and O2-surface in a big box, let them far enough that > there is no interaction between them > Or the two ways is not right? > Thank you very much. > Regards, > Gao Min >
