Import g and D tensors from CASSCF calculations

[radovanh]

Hello

I am dealing with polynuclear Co complex, and I have at my disposal results from CASSCF/NEVPT2 calculations in ORCA 5.0 for each Co(II) ion.
Now, I would like to import/load, D-tensors and g-tensors from the outputs and evaluate impact of isotropic exchange among spin centers.

For g-tensors, ORCA output for one of Co(II) ions is as follows:

Code: Select all

g-matrix:
    2.242238     0.030604    -0.008689 
    0.030925     2.281473    -0.014143 
   -0.008715    -0.014366     2.225566 

g-factors:
    2.221765     2.225528     2.301985 iso =     2.249759

g-shifts:
    0.219445     0.223209     0.299666 iso =     0.247440
 Orientation: 
  X           0.2807307    0.8359341    0.4715978
  Y           0.0836562   -0.5107983    0.8556207
  Z           0.9561338   -0.2007469   -0.2133278

and for D-tensors as

Code: Select all

Raw matrix (cm-1):
    2.341580    -2.569509     0.881821 
   -2.569509    -0.760228     1.301480 
    0.881821     1.301480     3.636078 

Eigenvalues (cm-1):
    3.738920     4.082694    -2.604183 

Eigenvalues (traceless) (cm-1):
    1.999776     2.343550    -4.343326 

Eigenvectors:
    0.751395     0.451724    -0.480990 
   -0.539168     0.000086    -0.842198 
   -0.380400     0.892158     0.243620 

Euler angles w.r.t. molecular frame (degrees):
    -66.9075      75.8997     -60.2687

D   =   -6.514990  cm-1
E/D =    0.026383

Reading EasySpin documentation, I think that I can use "Raw matrix' from ORCA to define D-tensor for each ion.
The same could be eventually used for g-tensors, However, I am NOT sure that the g-matrix should not be somehow rotated?

Or is there another way how to import parameters?

Thank you in advance for any advice

[Stefan Stoll]

Use the raw matrices for both g and D. ORCA reports them in the same frame, so they are consistent. There is no need to rotate them.

If you want, you can change into the g eigenframe by diagonalizing g, but then you need to transform D into the g eigenframe as well. But this will have no effect on the simulated spectrum, it's just a change of reference frame.

[radovanh]

Thank you.