Magnetic measurements and the nature of crystal field in Nd-2(SO4)(3)center dot 8H(2)O

Magnetic measurements on octahydrated neodymium sulphate have been carried out in the temperature range 80 to 300 K and analysis of the results has been performed using a crystal field of D-4h symmetry. The most rigorous approach of direct diagonalization of the Hamiltonian matrix constructed in the complete basis of states belonging to all atomic terms of the Nd3+ ion has been employed to evaluate the set of energy level parameters including crystal field parameters. The Hamiltonian consists of terms representing free ion (Coulomb and spin-orbit), crystal field, and two-body configuration interactions. It has also been demonstrated that for a correct evaluation of crystal field parameters it is absolutely necessary to work with a complete basis in the rigorous framework rather than with a partial basis.