The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

Dear Zeming,

It might be that your vacancy level is degenerate, and only partly  
occupied ...
You should then treat your system as a metal (see the occopt and  
tsmear input variables).

Xavier


On 02 Feb 2007, at 09:01, zmq.lyao@gmail.com wrote:

> Dear Abinit users,
>      I encounter a problem when I do a defect calculation. When I  
> perform a structure optimization of a supercell with a vacancy, the  
> SCF can't converge. The force and energy always oscillate and don't  
> decrease. Because of this, the structure optimization can't  
> continue. I have tried the iprcel and diemix parameter, but it  
> still don't work. Anybody has some suggestions to solve this  
> problem? Thanks in advance.
>
> Regard,
> Zeming
>
> The input files is as following :
> ----------------
> optcell 0
> ionmov  2
> ntime  100
> nstep  200        # Maximal number of SCF cycles
> dilatmx 1.05
> ecutsm  0.5
> toldff = 1.0D-4
> tolmxf = 1.0D-3
> prtgeo 1
> prtden 0
> prtwf 0
>
> iprcel 49
> diemix 0.7
> ecut 70
>
> #Definition of the unit cell
> acell 14.703085  14.703085  22.539888       # 2X2X2
> angdeg 90 90 120
> chkprim 0
> brvltt 0
> #Definition of the atom types
> ntypat 2
> znucl 57 8
> natom 39
> typat 8*1 7*2 8*1 16*2
> xangst
>  1.123   1.945   1.455
>  1.123   1.945   7.418
>  1.123   5.835   1.455
>  1.123   5.835   7.418
>  4.492  -0.000   1.455
>  4.492  -0.000   7.418
>  4.492   3.890   1.455
>  4.492   3.890   7.418
>  1.123   1.945   3.856
>  1.123   1.945   9.820
>  1.123   5.835   3.856
>  1.123   5.835   9.820
>  4.492  -0.000   9.820
>  4.492   3.890   3.856
>  4.492   3.890   9.820
>  2.246   0.000   4.509
>  2.246   0.000  10.473
>  2.246   3.890   4.509
>  2.246   3.890  10.473
>  5.615  -1.945   4.509
>  5.615  -1.945  10.473
>  5.615   1.945   4.509
>  5.615   1.945  10.473
>  2.246   0.000   2.107
>  2.246   0.000   8.071
>  2.246   3.890   2.107
>  2.246   3.890   8.071
>  5.615  -1.945   2.107
>  5.615  -1.945   8.071
>  5.615   1.945   2.107
>  5.615   1.945   8.071
>  0.000   0.000   0.000
>  0.000   0.000   5.964
>  0.000   3.890   0.000
>  0.000   3.890   5.964
>  3.369  -1.945   0.000
>  3.369  -1.945   5.964
>  3.369   1.945   0.000
>  3.369   1.945   5.964
>
>
> #Definition of the k-point grid
> kptopt 0
> kpt 0 0 0