Nuclear Quadrupole Interaction (EFG)¶

EFG
   Enabled Yes/No
End

EFG

Type

Block

Description

The electronic charge density causes an electric field, and the gradient of this field couples with the nuclear quadrupole moment, that some (non-spherical) nuclei have and can be measured by several spectroscopic techniques. The EFG tensor is the second derivative of the Coulomb potential at the nuclei. For each atom it is a 3x3 symmetric and traceless matrix. Diagonalization of this matrix gives three eigenvalues, which are usually ordered by their decreasing absolute size and denoted as V_{xx}, V_{yy}, V_{zz}. The result is summarized by the largest eigenvalue and the asymmetry parameter.

Enabled

Type

Bool

Default value

No

GUI name

EFG (electric field gradient): Calculate

Description

Compute the EFG tensor (for nuclear quadrupole interaction).

This option honors the SelectedAtoms key, in which case only the EFG will be calculated for the selected atoms.