In the two previous steps of this tutorial, we have generated the broken symmetry (BS) solution for the Fe4S4 cubane using alternatively the SpinFlip and ModifyStartPotential options. Here, we will analyze this BS solution viewing the Fe spin densities using ADFview, and confirm that the spin allignment of the iron sites is 2↑:2↓ This type of analysis can also be powerfully used during presentations and for scientific illustrations.
Select your FeS_BS_SPINFLIP calculation in ADFjobs Select the 'View' command from the 'SCM' menu
You should see the [Fe4S4(SH)4]2- model in the ADFview window now. We have optionally selected FeS_BS_SPINFLIP.t21, while FeS_BS_MODIFYSTARTPOTENTIAL.t21 could also be used for this purpose.
In ADFview, click the Fields drop-down menu and select Calculated (alternatively, issue Ctrl-F command).
Now, you should see the two blank tab fields right to the Field:Calculated at the bottom of the ADFview window, separated by the minus '-' sign .
Click the left blank tab menu and select Density A → SCF check box:
ADFview will take a moment now to calculate the corresponding density for spin-α ('Density A') electrons.
Next, click the right blank tab menu and select Density B → SCF check box.
Note that the minus '-' sign separating the tabs implies that we have requested ADFview to calculate the 'spin-α - spin-β' density field. ADFview automatically assigns 'C-1' title to this field, see left to the Field:Calculated. We will visualize this 'C-1' field using one of the available ADFview options now.
Click the Add drop-down menu and select Isosurface: Double (+/-) (alternatively, issue Ctrl-D command). Click the blank tab right to the Isosurface: Double appeared at the bottom of the ADFview, and select Other → 1 → C-1:
You should see now the two Fe ions surrounded by blue blobs (spin up,↑) and the other two by red blobs (spin down,↓):
Note that these are the greater two site numbers, Fe(6) and Fe(8), are spin down, as requested in your input specifications earlier in this tutorial. Also note that in the snapshot above, Show details options of the Isosurface: Double tab has been activated, and certain non-default options are entered to modify the default view of the spin density field (such as opacity, etc.).
In the same way you can also confirm that for the ferromagnetic HS case (file FeS_HS.t21), the visualization of the spin densities would display all the four Fe site surrounded by the blobs of the same color.
Congratulations, we are finally done with the tutorial on spin coupling in ADF!
