Energy Dependence of the D-D Reaction Cross Section at Low Energies

The energy variation of the approach cross section for the D-D reaction is calculated using several different methods. The simplest method assumes strong absorption inside the nuclear surface and uses the WKB approximation. The slope of the Gamow plot is in this case a constant. A strong absorption model, without WKB approximation, leads to negative corrections to this constant slope. A weak absorption model, which seems more applicable, gives both positive and negative corrections, depending on the depth of the nuclear potential. Finally, since the amount of absorption seems important, the effects of varying the absorption are studied using the optical model. The possible influence of the P-waves is also investigated. An experimental study of the energy dependence of the slope of the Gamow plot should give information on the optical potential which one deuteron sees when it approaches another deuteron.