26. Projected on atoms phonon DOS can also be calculated. Firstly, type Co to see the atomic numbers:

Mg atoms have numbers from 1 to 4, while O atoms - from 5 to 8.

27. To preview the projected DOS on all Mg atoms, type pD, then 1-4, and then D2 to preview:

There is some small difference only in the 3rd peak. Note that the very 1st peak is artificial. 

The projected DOS (PDOS) is shown alongside the total DOS. Contributions for each Mg atom are shown individually, but in this particular case they are exactly identical, so that you cannot distinguish between them.

28. Now, type pD, then 1 5 to get the DOS on one Mg and one O atoms, and then again D2 to preview:

We see that the first two peaks (smaller frequencies) are due mostly to Mg atoms (number 1), while the last three peaks - to O (number 5), as we have already seen when analysing the corresponding eigenvectors (normal modes).

29. Finally, we discussed above that three methods can be chosen to calculate the force-constant matrix from atomic forces. The DOS gives a very simple means of checking the three methods by displaying the DOS calculated by either of them on the same graph. Use Pr for that:

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