[Wien] Structure optimization of Beta -Sn

[Xavier Rocquefelte]

Dear Shamik

I will do as I do with my colleagues who are learning how to use WIEN2k ;)

Use the cif file I previously sent. If you directory is named Beta-Sn, 
rename the cif file Beta-Sn.cif.

Then use cif2struct in this way: cif2struct Beta-Sn.cif. It will 
generate Beta-Sn.struct

Then initialize the calculation and read carefully what WIEN2k is saying.

You will see this message when doing sgroup:

 >   sgroup    (08:56:30) 0.000u 0.000s 0:00.00 0.0%    0+0k 0+8io 0pf+0w
   Names of point group: -4m2   -4m2   D2d
warning: !!! Struct file is not consistent with space group found.
Number and name of space group: 141 (I 41/a m d) [origin choice 2]
warning: !!! Struct file is not consistent with space group found.
-----> check in  TT.outputsgroup  for proper symmetry, compare
        with your struct file and later with  TT.outputs
        sgroup has also produced a new struct file based on your old one.
        If you see warnings above, consider to use the newly generated
        struct file, which you can view (edit) now.
-----> continue with symmetry (old case.struct) or use/edit 
TT.struct_sgroup ? (c/e)
e

You see that WIEN2k is not happy with this setting and more specifically 
WIEN2k has only one origin choice for this space group (the second one) 
while the structure I sent you and the one you were using is based on 
the origin choice 1. But WIEN2k helps you and proposes to generate the 
structure file with the origin choice 2.

Thus you must use the new file.

e
-----> Do you want to use the new struct file  ? (y/n)
y
  next is nn
 >   nn    (08:57:51)  specify nn-bondlength factor: (usually=2) [and 
optionally dlimit, dstmax (about
   1.d-5, 20)]
2
  DSTMAX:   22.0000004768372
  iix,iiy,iiz           5           5           5 55.0996900000000
    55.0996900000000        30.0598750000000
  NAMED ATOM: Sn1       Z changed to IATNR+999 to determine equivalency

     ATOM  1  Sn1        ATOM  1  Sn1
  RMT(  1)=2.50000 AND RMT(  1)=2.50000
  SUMS TO 5.00000  LT.  NN-DIST= 5.71128
NN ENDS
0.004u 0.000s 0:01.51 0.0%    0+0k 0+32io 0pf+0w
-----> check in  TT.outputnn  for overlapping spheres,
        coordination and nearest neighbor distances
-----> continue with sgroup or edit the TT.struct file (c/e)
c
  next is sgroup
 >   sgroup    (08:58:02) 0.000u 0.000s 0:00.00 0.0%    0+0k 0+8io 0pf+0w
   Names of point group: -4m2   -4m2   D2d
Number and name of space group: 141 (I 41/a m d) [origin choice 2]
-----> check in  TT.outputsgroup  for proper symmetry, compare
        with your struct file and later with  TT.outputs
        sgroup has also produced a new struct file based on your old one.
        If you see warnings above, consider to use the newly generated
        struct file, which you can view (edit) now.
-----> continue with symmetry (old case.struct) or use/edit 
TT.struct_sgroup ? (c/e)
c

And as you can see you have no more warnings.

Best regards,

Xavier