In principle you are doing it ok. Are you using the latest mbj routines with all updates discussed in the mailing list ?
Still, I could imagine that in the surface region (low density) the mBJ potential diverges somehow, but I don't know this. Are the Fourier coefficients of Vxc (printed in case.output0) converging ? (There is a list of (h k l) with (0 0 i) and i ranges from 0 to some maximum. The corresponding fourier coefficient is large for i=0 and i=max, but in the "middle" they should be significantly smaller.) Alternatively, try a surface calculations with a "small vacuum" only and see if mBJ can handle this. Am 05.01.2012 10:06, schrieb archieve mail: > Hi Blaha, > > There is a paragraph about surface with mBJ in the usersguide. > " > The TB-mBJ potential uses an average of Drho=rho over the unit cell. This > does not make sense for > surfaces or molecules. In such cases, run a similar bulk structure first, > then cp case bulk.grr to > case.grr and remove case.in0 grr. This runs mBJ with a fixed value of ?c?. > " > > What does 'a similar bulk structure' mean? Now I want to calculate slab along > (111) direction of NaCl > structure. At first I converge a mBJ calculation of original NaCl structure > with just two atoms. Then > I copy bulk.grr to slab.grr to do the mBJ calculation. However the > calculation divergence even if > mixer is PRATT with mix beta 0.001. > > May be there is some faults in my calculation. Can you help me? > > Thanks a lot. > > Best, > > Yonghong Zhao > > > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien -- P.Blaha -------------------------------------------------------------------------- Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 Email: blaha at theochem.tuwien.ac.at WWW: http://info.tuwien.ac.at/theochem/ --------------------------------------------------------------------------