[Wien] PHONON calculation

[puday at iitk.ac.in]

Dear Prof Blaha and WIEN user,
I am doing PHONON calculation of "AlNi" as given example in the manual.I
am making the supercell 2x2x2(16 atoms) of this cubic symmetry using
phonon and I get a file *.d45 and this file I am using the input structure
file in WIEN2K.
Now I am running init_phonon_lapw
I am putting nn=2
and this warning is coming.....

    ATOM 16  Ni         ATOM  8  Al
 RMT( 16)=2.28000 AND RMT(  8)=2.02000
 SUMS TO 4.30000  LT.  NN-DIST= 4.70099
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
 WARNING: Mult not equal. PLEASE CHECK outputnn-file
 WARNING: ityp not equal. PLEASE CHECK outputnn-file
FORTRAN STOP NN created a new CASE.STRUCT_NN FILE
0.021u 0.001s 0:01.22 1.6%      0+0k 0+0io 0pf+0w
-----> check in  case_1.outputnn  for overlapping spheres,
       coordination and nearest neighbor distances
-----> DO YOU WANT TO USE THE NEW case_1.struct_nn file (y/n)


If I accept this new structure file and new space group 99 (P 4 m m) then
the program is running but while calculating Hellmann-Feynman forces and
dispersion curve I am not getting same as given in the example. Forces and
Dispersion curve going into negative!!


One thing is written in the WIEN2K user manual I am putting that line here.

Please use mainly nn to reduce equivalent atoms. sgroup might change the
unitcell and than the collection of forces into the original supercell is
not possible (or quite difficult).

I don't understand these lines.
Any help will be highly appreciated.


Regards,
Uday
Dept.of Physics
Indian Institute of Technology, Kanpur