ONE-ELECTRON AND 2-ELECTRON ATOMIC SCREENING IN FUSION REACTIONS

Recent laboratory experiments have measured fusion cross sections at c enter-of-mass energies low enough that the effects of atomic electrons are important. To extract the cross section for bare nuclei from thes e data (as required for astrophysical applications), it is necessary t o understand these screening effects. We present a model in which the evolution of the electron wave function is treated dynamically in the time-dependent Hartree-Fock scheme, while the motion of the nuclei is treated classically. We have calculated screening in the d + H-2 and d + He-3 reactions and give the effective screening energy U(e) at smal l internuclear separations as a function of E. The resulting U(e) valu es do not exceed the previously established adiabatic limits, and thus cannot explain the higher screening energies derived from experiment.