Plotting the orbitals

Now what is the character of the bands? Let us first examine this narrow band at about -0.5 Hartree.

Open ADFview with the menu 'View' command from the 'SCM' menu.
In ADFview: select the 'Isosurface Double (+/-)' command from the 'Add' menu.

In the bar at the bottom of the window, you can select which field to show.

Select the lowest band (k=0,0,0)

From the label you can see that it has an energy of -0.4641 and the coordinates are (0,0,0). The cursor will go to the busy state, and after a while you will see the orbital:

If you rotate it a bit and toggle the isosurface on and off, you can convince yourself that this orbital is located around the small atom, which is the Chlorine.

Toggle the periodic view (the menu 'Periodic>Show Periodic' command from the 'View' menu).

Obviously this is the 3s band of Cl. The strange truncated spheres are due to contributions of neighboring cells.

Let us now take a look at the orbital with the lowest energy of the second band (the first one with an energy not around -0.4):

Select the lowest orbital of the second band (with energy about -0.08)

This orbital looks like:

and it clearly consists of a p orbital on the Cl. The part near the Na comes from Chlorine atoms in neighboring cells.

It is generally easier to interpret orbitals at k=(0,0,0). The second band at this point looks like

From these orbital pictures we can conclude that the valence band is indeed mainly of Chlorine-p character.

You may want to check the lowest orbitals of the (unoccupied) conduction band.

Check the lowest orbitals of the conduction band
Do you see a strong Na character in them?