[Pw_forum] Normalization of the atomic wave functions

[Henning Glawe]

Moin,
I am at the momemt trying to understand how the atomic states used in an
LDA+U calculation are normalized. I inserted code to print out the
normalization into the k-loop of the new_ns subroutine:

[...]
  COMPLEX(DP) :: hg_norm
[...]
  ALLOCATE(wfcatom(npwx,natomwfc))

  DO ik = 1, nks
     IF (lsda) current_spin = isk(ik)
     IF (nks.GT.1) READ (iunigk) npw, igk
     IF (nks.GT.1) CALL davcio (evc, nwordwfc, iunwfc, ik, - 1)

     CALL davcio (swfcatom, nwordatwfc, iunsat, ik, - 1)
     CALL davcio (wfcatom, nwordatwfc, iunat, ik, -1)
     DO i = 1, natomwfc
        hg_norm=ZDOTC(npw, wfcatom(1,i), 1, swfcatom(1,i), 1)
        write( 43, '(i4.4,1x,i1.1,1x,i3.3,1x,2e20.10)') ik, current_spin, i, hg_norm
     ENDDO
[...]

so basically I am calculating <\phi^I_k|S|\phi^I_k> (the S operator 
being related to the relaxed norm conservation in the case of ultrasoft
pseudopotentials).  I assumed this to be always 1.

However, running the FeO example in the QE distribution, I obtain a spektrum
of values, most of them between 0.9 and 1.1. The norm of one atomic state of
the example system and its spin-counterpart are spread quite widely, between 
0.3 and 3.85 (?).

So somehow I get the impression that I do not understand how the atomic 
states are normalized in pwscf...

-- 
c u
henning