Coupled-cluster calculation of the static polarisabilities and hyperpolarisabilities of magnesium

The dipole and the quadrupole polarisabilities, the dipole-dipole-quadropole and second dipole hyperpolarisabilities of the magnesium atom are calculated with an extensive basis set by using the coupled-cluster model within the finite-field approximation. At the highest level, the single-reference coupled-cluster double-excitation model corrected to include contributions of single and triple excitations in the so-called CCD+ST (CCD) scheme, the results are 70.89, 810.0, -8.02x103 and 1.00x105 a.u., respectively, in good argeement with previous single-reference low-order perturbation theory results. (orig.)