Interaction potentials and momentum transfer in ionic collisions: Uranium

The effect of elastic collisions of ${\mathrm{U}}^{+}$ with U, ${\mathrm{U}}^{+}$, and ${\mathrm{U}}^{2+}$ in a ${\mathrm{U}}^{+}$ plasma has been investigated. The required potential-energy curves were calculated by means of the electron-gas (Gordon-Kim-Rae) statistical method. An effective polarization potential was added to the ion-neutral potential curve. Collisional phase shifts were evaluated by the semiclassical JWKB method using a very efficient algorithm. Modifications necessary to take into account the long-range shielded Coulomb potential in ion-ion collisions are described. Momentum-transfer and viscosity cross sections, without charge transfer, are presented and their dependences on the long- and short-range potentials are examined.