3D field visualization with BAND
********************************

With AMSview you can visualize three-dimensional fields from the
results of a BAND Calculation (**runkf** file).

Following is a list of relevant fields, with a short explanation and
illustrative pictures (from a simple non-periodic H_2 calculation).
All fields are in atomic units (a.u.).

Total_Density (rho)
   The electronic density \rho (r). The integral of the electronic
   density over the whole space (or, for periodic systems, over the
   unit cell) equals the total number of electrons (valence + core).

   [image]

Deformation density (rho(deformation))
   The deformation density is the difference between total density
   \rho (r) and reference density \rho_\text{reference} (r)

      \rho_\text{deformation} (r) =  \rho (r) - \rho_\text{reference}
      (r)

   The reference density \rho_\text{reference} (r) is defined as the
   sum of densities of spherical spin-unrestricted isolated atoms.

   The deformation density is electrically neutral, i.e. its integral
   over the whole space (or, for periodic systems, over the unit cell)
   is zero. Positive values of deformation density indicate density
   accumulation wrt isolated atoms; negative values represent density
   depletion. In our H_2 example, the deformation density shows how
   there is electron accumulation in the bonding region between the
   two hydrogen atoms.

   [image]

SCF_CoulombPot (v(coulomb))
   The total Coulomb potential (nuclear + electronic potentials).
   BANDs convention for the Coulomb potential: the potential of
   positive charges (like nuclei) is **negative**, while the potential
   of negative charges (like electrons) is **positive**. In our
   example, the nuclear potential (negative) is larger than the
   electronic potential (positive) in the region of space near the H_2
   molecule.

   [image]

   Note:

     The sign convention for potentials in **BAND** is the opposite to
     the **ADF** sign convention.

SCF_CoulombDeformation (v(coulomb/deformation))
   The Coulomb potential originating from the (overall neutral)
   deformation density.

   [image]

xc pot (vxc(rho))
   The Exchange Correlation (XC) potential. Electrons are *attracted*
   by negative XC potentials (just like they are *attracted* by the
   negative nuclear Coulomb potential)

   [image]

Orbitals (occupied/virtual)
   The Kohn-Sham orbitals.

   Note:

     Be aware that there is an over-all arbitrariness in the sign of
     the orbitals

   Here we show the occupied and first virtual orbital of H_2.

   [image][image]
