The collisional system ${\mathrm{Si}}^{4+}+\mathrm{He}$ has been studied over a range of mean relative ion kinetic energy going from ${10}^{-2}$ to ${10}^2\mathrm{e}\mathrm{V}/\mathrm{a}\mathrm{m}\mathrm{u}.$ In the low-energy range, a time-dependent wave-packet approach is used both in the diabatic and the adiabatic representation using two different propagator techniques. The agreement between the two sets of results assess the accuracy of the present numerical approach. Above 2.5 eV/amu., a semiclassical eikonal calculation is performed, which includes the Coriolis couplings. Finally, the rate constant is calculated and compared with the other theoretical data as well as with the experimental value of [Fang and Kwong, Phys. Rev. A 59, 342 (1999)]. The present results confirm the order of magnitude of previous theoretical values.

• Received 31 August 2000

DOI:https://doi.org/10.1103/PhysRevA.63.042704