[Pw_forum] charge density with denser grid and wrong cube file

[Thomas Gruber]

Hallo all,

I have two problems:
1. I like to have the charge_density.xsf/*.cube with output_format=5/6, 
but with a denser grid than the FFT grid. nx,ny,nz are ignored in this 
case. They work for output_format=3 with an orthorhombic box, but I want 
my unit cell.

2. The output format for *.xsf works fine, but not for *.cube. For xsf 
the data_grid is x+1,y+1,z+1, but not for cube (x,y,z). The *.cube also 
needs x+1,y+1,z+1 to get the write volume, atom positions and no offset 
along the unit cell surface for the charge density. I tried to correct 
the cube.f90 in PP but the charge density data is still not correct. I 
increased nr# by 1 in each case:

   WRITE(ounit,*) 'Cubfile created from PWScf calculation'
   WRITE(ounit,*) ' Total SCF Density'
!                        origin is forced to (0.0,0.0,0.0)
   WRITE(ounit,'(I5,3F12.6)') nat, 0.0d0, 0.0d0, 0.0d0
   WRITE(ounit,'(I5,3F12.6)') nr1+1, (alat*at(i,1)/dble(nr1),i=1,3)
   WRITE(ounit,'(I5,3F12.6)') nr2+1, (alat*at(i,2)/dble(nr2),i=1,3)
   WRITE(ounit,'(I5,3F12.6)') nr3+1, (alat*at(i,3)/dble(nr3),i=1,3)

   DO i=1,nat
      nt = ityp(i)
      ! find atomic number for this atom.
      at_num = atomic_number(trim(atm(nt)))
      at_chrg= dble(at_num)
      ! at_chrg could be alternatively set to valence charge
      ! positions are in cartesian coordinates and a.u.
      !
      ! wrap coordinates back into cell.
      tpos = matmul( transpose(bg), tau(:,i) )
      tpos = tpos - nint(tpos - 0.5d0)
      inpos = alat * matmul( at, tpos )
      WRITE(ounit,'(I5,5F12.6)') at_num, at_chrg, inpos
   ENDDO

   DO i1=1,nr1+1
      DO i2=1,nr2+1
         WRITE(ounit,'(6E13.5)') (rho(i1,i2,i3),i3=1,nr3+1)
      ENDDO
   ENDDO

Can someone give me the correction for cube.f90 and a way to increase 
the data_grid density for the output_format=5/6?

Sincerely,

Thomas Gruber

-- 
Thomas Gruber
Institut für Theoretische Physik
TU Bergakademie Freiberg
Leipziger Str. 23, 09599 Freiberg, Germany
Tel: +49 (0)3731 392006
Email: thomas.gruber at physik.tu-freiberg.de