Neutron magnetic form factors of uranium ions

The radial ji integrals, which contribute to the neutron magnetic form factors, of several uranium ions (U3+, U4+, U5+) are determined from fully relativistic Dirac-Fock wave functions. The expectation values of the rn operators, rn, with n=-3, 2, 4, and 6 are given for the uranium ions. The possibility of determining the ionization state by magnetic scattering experiments is discussed. The radial ji integrals are used to analyze the experimental form factor of US determined by Wedgwood. Satisfactory agreement is found by choosing a 5f2 Γ1 crystal-field ground state with a large internal exchange field inducing ferromagnetism. Contributions to the magnetic scattering from 6 d electrons are found to be negligible for values of sinθλ>0.2 -1.