Nuclear Quadrupole Interaction (EFG)

EFG (block type)

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.

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