DOS/PDOS for covalent systems

[pen2kin]

Hi,

I have a couple of covalent systems (mainly oxides and sulfide surfaces). I am calculating PDOS for different surface atoms. I used K 1x1x1 (gamma point) calculation for relaxation using gaussian smearing. Then calculated DOS by following two methods:

1. K4x4x1 (Gamma centered) and Tetrahedron scheme
2. K1x1x1 and Gaussian smearing scheme

The two PDOS are very different. For gas phase molecules method 2 only gives PDOS which I can understand better as a chemist. Please advice me which strategy would be better. I want to see how gas phase PDOS changes on chemisorption.

Cheers!

[lcyin]

For DOS and Band calculations, I think a SCF charge density must be obtained by a SCF static calculation using a same K-mesh setting.