Comparison between theoretical and experimental screening energies for the 2H(d,p)3H reaction in metallic environments and its consequences for nuclear reactions at room temperature

Study of the the 2H(d,p)3H and 2H(d,n)3He reactions at very low energies in deuterized metallic targets provides a unique possibility to test models of the electron screening developed for dense astrophysical plasmas. Here, we compare the experimental screening energies obtained by our group as well as other authors for different target materials with theoretical predictions based on an improved dielectric function theory. The calculations are performed within the self-consistent regime and include polarization of both quasi-free and bound electrons. Additionally, the cohesion screening, arising from different binding energies of deuterons and α-particles in crystal lattices, is taken into account. This approach allows to derive the deuteron-deuteron potential in metallic environments and to determine an energy dependence of the effective screening energy. Applying this result, the theoretical cross sections, thick target yields as well as nuclear reaction rates of the d+d reactions are calculated down to the energies corresponding to room temperature. Consequently, a comparison of the experimental results obtained in accelerator experiments at higher energies with those achieved in the heavy-water electrolysis experiments will be presented. (author)