[Wien] how to use non-default ROTLOC (local rotation matrix)

[Peter Blaha]

What you need is a consistency between local coordinate system (rotation 
matrix), LM values in the density expansion (in2) and k-mesh.
let me explain:
symmetry calculates the proper L,M values of the symmetriezed density 
expansion ONLY for it's preferred coordinate system, i.e. where the axis 
of highest symmetry is z,...

So when you put an arbitrary rotation matrix, you have two choices:
a) You must find out, which L,M values are allowed by this symmetry and 
put them in the in2 file yourself. There are routines in various WIEN 
programs like in QTL or in AFMINPUT, which determine how the Y- LM 
behave under rotations,... and this could in principle be used to 
generate a code which does this selection for you according to the 
guidelines indicated in D.Singhs book.
b) You select all LM values, however, in this case you must "symmetrize" 
the density by using a "full" k-mesh (or again, a symmetrization as done 
in the QTL progeam). This is similar as what we have done so far for the 
telnes calculations for the off-diagonal elements, but now you need that 
for all diagonal parts and L.ne.0 too.

Regards   

> How does one use non-default local rotation matrices?  (Non-default means : I choose another matrix than the one proposed by sgroup or symmetry).  Is one free to use any matrix or are there restrictions?  Is further editing of case.struct necessary?  Any tips and tricks?
>  
> I had thought of simply editing case.struct (changing ROTLOC's, in my case to a completely arbitrary rotation away from all symmetric directions) and case.in2 (adding all l,m - components).  After that, lstart, kgen, dstart, run_lapw.
> Unfortunately, this doesn't seem to work (dstart and lapw0 give results that deviate from a calculation with the default ROTLOC, and after that lapw1 crashes with SECLR4 error).
>  
> I'm using a fairly simple case.struct (careful : some tabs misbehaved when copying)
>  
> jaws> more draai.struct
> MnO2
> P   LATTICE,NONEQUIV. ATOMS  2
> MODE OF CALC=RELA unit=ang
>   8.322357  8.322357  5.434855 90.000000 90.000000 90.000000
> ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
>           MULT= 2          ISPLIT=99
>       -1: X=0.50000000 Y=0.50000000 Z=0.50000000
> Mn         NPT=  781  R0=0.00005000 RMT=    2.0000   Z: 25.0
> LOCAL ROT MATRIX:   -0.2126195-0.8648664-0.4547516
>                      0.5708473-0.1098742-0.2417957
>                      0.1591555-0.4898303 0.8571673
> ATOM  -2: X=0.30500000 Y=0.69500000 Z=0.00000000
>           MULT= 4          ISPLIT=99
>       -2: X=0.69500000 Y=0.30500000 Z=0.00000000
>       -2: X=0.19500000 Y=0.19500000 Z=0.50000000
>       -2: X=0.80500000 Y=0.80500000 Z=0.50000000
> O          NPT=  781  R0=0.00010000 RMT=    1.5500   Z:  8.0
> LOCAL ROT MATRIX:   -0.2224228-0.9672608-0.1222074
>                     -1.0403100 0.2410450-0.1682040
>                      0.1921547 0.0793967-0.9781476
>   16      NUMBER OF SYMMETRY OPERATIONS
> -1 0 0 0.0000000
>  0-1 0 0.0000000
>  0 0-1 0.0000000
>        1
> -1 0 0 0.0000000
>  0-1 0 0.0000000
>  0 0 1 0.0000000
>        2
>  0-1 0 0.0000000
> -1 0 0 0.0000000
>  0 0-1 0.0000000
>        3
>  0-1 0 0.0000000
> -1 0 0 0.0000000
>  0 0 1 0.0000000
>        4
>  0 1 0 0.0000000
>  1 0 0 0.0000000
>  0 0-1 0.0000000
>        5
>  0 1 0 0.0000000
>  1 0 0 0.0000000
>  0 0 1 0.0000000
>        6
>  1 0 0 0.0000000
>  0 1 0 0.0000000
>  0 0-1 0.0000000
>        7
>  1 0 0 0.0000000
>  0 1 0 0.0000000
>  0 0 1 0.0000000
>        8
>  0 1 0 0.5000000
> -1 0 0 0.5000000
>  0 0 1 0.5000000
>        9
>  0-1 0 0.5000000
>  1 0 0 0.5000000
>  0 0-1 0.5000000
>       10
>  0-1 0 0.5000000
>  1 0 0 0.5000000
>  0 0 1 0.5000000
>       11
> -1 0 0 0.5000000
>  0 1 0 0.5000000
>  0 0-1 0.5000000
>       12
> -1 0 0 0.5000000
>  0 1 0 0.5000000
>  0 0 1 0.5000000
>       13
>  1 0 0 0.5000000
>  0-1 0 0.5000000
>  0 0-1 0.5000000
>       14
>  1 0 0 0.5000000
>  0-1 0 0.5000000
>  0 0 1 0.5000000
>       15
>  0 1 0 0.5000000
> -1 0 0 0.5000000
>  0 0-1 0.5000000
>       16
> 
> default ROTLOC's are
> LOCAL ROT MATRIX:    0.7071068 0.7071068 0.0000000
>                     -0.7071068 0.7071068 0.0000000
>                      0.0000000 0.0000000 1.0000000
> and
> LOCAL ROT MATRIX:    0.0000000 0.7071068-0.7071068
>                      0.0000000 0.7071068 0.7071068
>                      1.0000000 0.0000000 0.0000000
> 
> default case.in2 is 
>   0 0  2 0  2 2  4 0  4 2  4 4  6 0  6 2  6 4  6 6
>   0 0  1 0  2 0  2 2  3 0  3 2  4 0  4 2  4 4  5 0  5 2  5 4  6 0  6 2  6 4  6 6
>  
> modified case.in2 is
>   0 0  1 0  1 1 -1 1  2 0  2 1 -2 1  2 2 -2 2  3 0  3 1 -3 1  3 2 -3 2  3 3 -3 3
>   4 0  4 1 -4 1  4 2 -4 2  4 3 -4 3  4 4 -4 4  5 0  5 1 -5 1  5 2 -5 2  5 3 -5 3
>   5 4 -5 4  5 5 -5 5  6 0  6 1 -6 1  6 2 -6 2  6 3 -6 3  6 4 -6 4  6 5 -6 5  6 6
>  -6 6
>   0 0  1 0  1 1 -1 1  2 0  2 1 -2 1  2 2 -2 2  3 0  3 1 -3 1  3 2 -3 2  3 3 -3 3
>   4 0  4 1 -4 1  4 2 -4 2  4 3 -4 3  4 4 -4 4  5 0  5 1 -5 1  5 2 -5 2  5 3 -5 3
>   5 4 -5 4  5 5 -5 5  6 0  6 1 -6 1  6 2 -6 2  6 3 -6 3  6 4 -6 4  6 5 -6 5  6 6
>  -6 6
> 
>  
> spacegroup is 136 (P 42/m n m)
> (pointgroups mmm and mm2)
>  
>  
>  
>  
>  
> Thanks,
>  
>  
>  
> Kevin Jorissen
>  
> EMAT - Electron Microscopy for Materials Science   (http://webhost.ua.ac.be/emat/)
> Dept. of Physics
>  
> UA - Universiteit Antwerpen
> Groenenborgerlaan 171
> B-2020 Antwerpen
> Belgium
>  
> tel  +32 3 2653249
> fax + 32 3 2653257
> e-mail kevin.jorissen at ua.ac.be
>  
> 


                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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