# [Wien] Query about SOC in WIEN2k

```Dear Dr. P. Blaha,

I am trying to calculate the magnetic anisotropy energy (MAE) for the
magnetic system Nd-metal. For this I tried couple of methods (energy
theorem and force theorem) to calculate MAE.```
```
Energy theorem:

step-1: Performed GGA+U ; Step-2: executed initso_lapw  for different
directions 001, 100 etc ; Step-3: Didn't put RLO (relativistic local
orbital in the .inso file)

Step-4: Performed runsp_lapw -so -orb -dm  -ec 0.000001 ; Step-5 Took
the difference of energies E[001] - E[100]

The above method give correct result in very few cases. Am I doing wrong
somewhere?

Force Theorem:

Will you please explain the steps correctly because I am confused while
doing the steps. I followed the below steps and this is not working for me.

Step-1: Performed GGA+U (runsp_lapw -dm -orb -ec 0.000001);

Step-2: initso_lapw (by taking below actions)

---->Add RLO for NONE, ALL, CHOOSE elements? (N/a/c) : N

Do you have a spinpolarized case (and want to run symmetso) ? (y/N) Y

Do you want to use the new structure for SO calculations ? (y/N)   N

Step-3: x lapwso -up

Step-4: x lapw2 -up

Step-5: x lapw2 -dn

Step-6:  MAE = 001(sum of eigenvalues up & down) - 100(sum of
eigenvalues up & down)

This force method is also not working properly. Will you please correct
me where I am doing wrong.

I also followed the following links for my above steps:

https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09408.html

http://zeus.theochem.tuwien.ac.at/pipermail/wien/2010-September/013730.html

Thank you,
R. Chouhan
```
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