[Wien] Understanding case.output1 with WFPNT: coefficients from interstitial region associated with reciprocal lattice vectors

[Peter Blaha]

Your problem comes from the local orbitals. The eigenvector listed in 
the output contains not only the coefficients of the (A)PW basis (which 
are correctly labeled by K), but (at the bottom) also the coefficients 
of the local orbital basis. Also these coefficients are labeled by a 
K-vector (because to each LO a phase factor exp(iKr) is attached), but 
the indicated to contribution of the LOs.
You should somewhere find the number of LOS for your case or you can see 
where they start when you check the manitude of K. K increases for the 
PW basis, but than "restarts" at a small K for the LOs.

Am 26.02.2017 um 13:20 schrieb Dara Goldar:
> Dear Wien2k community,
>
> I am trying to compute the overlap between different eigenfunctions
> calculated from a GaAs-run. In doing so, I've run into an issue
> regarding the wavefunction from region II, which is outputted in
> case.output1 through the program lapw1 (using WFPNT).
>
> The specific issue I have is that for a given k-vector and energy band,
> I am reading the same reciprocal lattice vector more than once, each
> time with different values of the coefficients.
>
>  I've copied a part from my GaAs.output1-file; an example of the above
> is found for k=(0,0,0), bands 1-9, for reciprocal lattice vector (-1,
> -1, -1) and (1, -1, -1) (highlighted).
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
> K=   0.00000   0.00000   0.00000            1
>       MATRIX SIZE   166  WEIGHT= 1.00  PGR:
>      EIGENVALUES ARE:
>      -2.2441103   -2.2441103   -2.2441103   -2.2430406   -2.2430406
>      -0.7539068   -0.7539068   -0.7539068   -0.7474829   -0.7474829
>      -0.6043444    0.3329249    0.3329249    0.3329249    0.3707415
>       0.6043473    0.6043473    0.6043473    0.8929301    1.0780723
>       1.0780723    1.1818337    1.1818337    1.1818337    1.4052914
>
>             0 EIGENVALUES BELOW THE ENERGY   -9.00000
>        ********************************************************
>
>
>
>
>
>    RECIPROCAL LATTICE VECTORS
>
>                     1.ENERGY   2.ENERGY   3.ENERGY   4.ENERGY   5.ENERGY
>   6.ENERGY   7.ENERGY   8.ENERGY   9.ENERGY
>    0   0   0
>                    0.000000   0.000000  -0.000000  -0.000000   0.000000
>  -0.000000   0.000000   0.000000  -0.000000       REALPART
>                    0.000000   0.000000  -0.000000  -0.000000   0.000000
>  -0.000000  -0.000000  -0.000000   0.000000       IMAGPART
>       .
>       .
>       .
>
> * -1  -1  -1*
> *                   0.000321  -0.000010   0.000029  -0.000000   0.000000
>   0.013505   0.000959  -0.001484  -0.000000       REALPART*
> *                   0.000184   0.000024  -0.000063   0.000000  -0.000000
>  -0.004805   0.004760   0.000770   0.000000       IMAGPART*
> *   1  -1  -1*
> *                   0.000136   0.000126   0.000200  -0.000000   0.000000
>   0.007245  -0.004415   0.008832  -0.000000       REALPART*
> *                   0.000064  -0.000120  -0.000223   0.000000  -0.000000
>  -0.004644   0.003845  -0.006747   0.000000       IMAGPART*
>   -1   1  -1
>                    0.000104   0.000107   0.000029  -0.000000   0.000000
>   0.005069  -0.011615  -0.001513  -0.000000       REALPART
>                    0.000091   0.000212  -0.000258   0.000000   0.000000
>  -0.006230   0.005351   0.001220   0.000000       IMAGPART
> *  -1  -1  -1*
> *                  -0.063399  -0.008318   0.021767  -0.000000   0.000000
>  -0.031423   0.031130   0.005038  -0.000000       REALPART*
> *                   0.110700  -0.003450   0.009852  -0.000000   0.000000
>  -0.088312  -0.006270   0.009704   0.000000       IMAGPART*
>   * 1  -1  -1*
> *                   0.022177  -0.041315  -0.076824   0.000000  -0.000000
>   0.030371  -0.025141   0.044119   0.000000       REALPART*
> *                  -0.046973  -0.043376  -0.068828   0.000000   0.000000
>   0.047376  -0.028869   0.057754  -0.000000       IMAGPART*
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
>
> Since each reciprocal lattice vector according to my GaAs.output1-file
> has more than one set complex of coefficients, I'm not sure how to
> interpret this. I've audaciously attempted to study the files 'wfpnt.f'
> and 'coors.f', but found no indication of mapping back to 1BZ or
> anything else I can think of which would explain why each reciprocal
> lattice vector is associated with more than one set of coefficients.
>
> In particular, I'm wondering if this should happen at all, and if so,
> which of the coefficients should I use when computing the overlap for a
> given band and k-vector?
>
>
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>

-- 
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
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