
This example shows how to calculate the Density of States (DOS)
projected onto molecular orbitals.

The calculation proceeds as follows (for the meaning of the cited input
variables see the appropriate INPUT_* file)

1) make a self-consistent calculation for the full system, which here
   is made of two H2 molecules. In this example, molecules have
   different H-H distance to change the splitting between
   bonding/antibonding orbitals (input=H2AB.scf.in,
   output=H2AB.scf.out).

2) make a self-consistent calculation for the molecular part, with the
   same cell / k-point parameters as for the full system. Here we can
   project on either of the two H2 molecules.
   (input=H2A.scf.in,H2B.scf.in, output=H2A.scf.out,H2B.scf.out).

3) use projfwc.x to project the crystal wavefunctions on an
   orthogonalized basis set of atomic orbitals for the full system and
   the molecular part
   (input=H2AB.projwfc.in,H2A.projwfc.in,H2B.projwfc.in,
   output=H2AB.projwfc.out,H2A.projwfc.out,H2B.projwfc.out). The
   projections are saved in files atomic_proj.xml files to be copied
   from $TMP_DIR/.

4) identify which wavefunctions of the orthogonalized basis set ot
   atomic orbitals of the full system correspond to the same set as in
   the molecular part (i.e., identify the proper range which will be
   denoted as i_atmwfc_beg_full to i_atmwfc_end_full, see outputs of
   step 3).

5) run molecularpdos.x providing in input the location of the
   atomic_proj.xml files for the full system and of the molecular
   part, and the ranges of atomic orbitals to be used
   (input=project_AB_onto_A.in,project_AB_onto_B.in,
   output=project_AB_onto_A.out,project_AB_onto_B.out).

6) if gnuplot is available, results are plotted to file
   project_AB_onto_A_B.ps which shows projection of the DOS of the
   combined system on sigma and sigma* orbitals of the two individual
   H2 molecules (which differ in energy because of different H-H
   distance).