Calculations of hyperfine parameters in antimony compounds

The electron contact density and electric-field gradient on the Sb nuclear position is calculated in a series of 22 Sb compounds, comprising metallic, covalent as well as ionic Sb(III) and Sb(V) systems. The full-potential linear-muffin-tin-orbitals method is used with the local-density-approximation for exchange and correlation effects. By comparison with experimental ¹²¹Sb and ¹²³Sb nuclear quadrupole resonance data and ¹²¹Sb M\"ossbauer data, the calibration constants relating measured quadrupole coupling constants and isomer shifts to the electric-field gradient and the electron contact density, respectively, are derived. This leads to an accurate determination of the quadrupole moment of the ¹²¹Sb nuclear ground state as Q=-66.9fm². The difference between the mean-square radius of the ¹²¹Sb nucleus in its excited isomeric and ground states is found to be Δ〈r²〉=-0.0521fm².