Spin-orbit coupling in an f-electron tight-binding model: Electronic properties of Th, U, and Pu

We extend a tight-binding method to include the effects of spin-orbit coupling and apply it to the study of the electronic properties of the actinide elements Th, U, and Pu. These tight-binding parameters are determined for the fcc crystal structure using the equivalent equilibrium volumes. In terms of the single-particle energies and the electronic density of states, the overall quality of the tight-binding representation is good and of the same quality as without spin-orbit coupling. The values of the optimized tight-binding spin-orbit coupling parameters are comparable to those determined from purely atomic calculations.