[Wien] accuracy problem after running x sgroup

[Peter Blaha]

Are you using WIEN2k_10 ???  It should not happen anymore.

Hexagonal lattice ???  min_lapw could have produced atomic positions, 
which are not completely equivalent anymore (like 0.3333333 and 
0.666666) because of rounding errors.

Check your atomic positions manually.

Am 23.10.2010 06:22, schrieb shamik chakrabarti:
> Dear wien2k users,
>
>                              we have done structure optimization (both
> volume and force) of a A2BCO4 type material. After optimization the
> maximum force on an atom is *2.036 mRy/a.u.* After optimization if we
> view the structure with xcrysden we can see that some atoms remain
> unbonded i.e. one or two free atom and the rest of the structure is
> connected through bond. Now my questions are:
>
>            (1) Can such a structure be stable although DFT has able to
> found a solution in which the energy of the unit cell and forces on the
> atoms are minimum?
>
>            (2) When I take this optimized struct file and tried to
> initilize and run a SCF with this struct file, after *x sgroup* command
> it will show :
> *Accuracy problem. Please run with different tolerance (x sgroup -settol
> .00000100)*
> *
> *
>                Now if we ignore this problem or we run the command x
> sgroup -settol 0.00000100, irrespective of that all the atoms got
> deleted after x symmetry command!!
>
>                So, my question is whether this optimized struct file is
> not feasible or is their any way to remove this accuracy problem?
>
> any response will be very helpful for us. Thanking you,
>
> with regards,
>
>
> --
> Shamik Chakrabarti
> Research Scholar
> Dept. of Physics & Meteorology
> Material Processing & Solid State Ionics Lab
> IIT Kharagpur
> Kharagpur 721302
> INDIA
>
>
>
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-- 
Peter Blaha
Inst.Materials Chemistry
TU Vienna
Getreidemarkt 9
A-1060 Vienna
Austria
+43-1-5880115671