THERMONUCLEAR REACTIONS IN MEDIUM AND HEAVY NUCLEI

A method is outlined by which thermonuclear reaction rates can be determined from the statistical properties of nuclei. Assuming that the contribution to the cross section of a given resonance is given by the Breit–Wigner single-level formula, the total rate is determined by integrating the product of the cross section, weighted by the nuclear level density, and the velocity over energy. The nuclear radiation widths were calculated on the assumption that electric-dipole transitions are dominant. The particle widths were determined by approximating the nuclear strength function by that value calculated for a black nucleus. Nuclear cross sections calculated in this manner are compared with experiment both for charged-particle reactions on lighter nuclei and for neutron-capture reactions proceeding on nuclei in the mass range A > 60. Good agreement is obtained in both cases.