Molcas Forum

pathirage

Member

Registered: 2025-02-02

Posts: 5

Electric field gradient

Hi,
I'm currently trying to calculate the electric field gradient (EFG) for the atom.

Below is the first part of my input.

>>export MOLCAS_MEM=64Gb
  &SEWARD &END
    CHOLESKY
    FLDG
    0
    COORD
    $Project.xyz
    BASIS
    Th.ANO-RCC-VTZP, F.ANO-XS-VDZP, Ca.ANO-XS-VDZ
    GROUP
    C1

I have used FLDG=0 in the gateway. And below is the part of the output for the first atom.

      Electric field gradient:
       (2*XX-YY-ZZ)/2          1.5*XY          1.5*XZ  (2*YY-ZZ-XX)/2          1.5*YZ  (2*ZZ-XX-YY)/2
          RR=XX+YY+ZZ
    1         -0.7046          0.0001          0.3512          1.3697          0.0000         -0.6651
      -272494316.8933

My questions are:
Is this the correct method to calculate EFG? Please let me know if not. (Note: I do not want to apply any external field.)
Do we need to diagonalize the matrix to obtain Vzz, Vxx, and Vyy? (according to above output what is Vzz?)
Also, can I know whether embedding or without embedding is good to calculate EFG? I obtained two different results, possibly due to the presence of external atoms.

I would really appreciate your guidance on this aspect of the EFG.
Thank you in advance.

Last edited by pathirage (2025-04-14 04:30:38)