Calculation of the Anisotropic Hyperfine Coupling in Cu(II) Bis(dithiocarbamate) and Cu(II) Bis(diselenocarbamate). A Formula for the Anisotropic Hyperfine Coupling Tensor

For a molecule with one unpaired electron a general formula is derived for the elements of the anisotropic hyperfine coupling tensor, taking into account all possible electron excitations. For a check of the formula the hyperfine coupling tensors are calculated for the copper atom in bis(N, N-diethyl dithiocarbamato) copper(II) and for the copper and selenium atoms in bis(N, N-diethyldiselenocarbamato) copper(II), using the iterative extended Hückel method. Both the calculated principal values of these tensors and the direction cosines of the principal axes are in good agreement with the experimentally observed ones.