Electron Capture and Nuclear Matrix Elements of Be7 †

We calculate the Be⁷ electron capture rate from continuum orbits as a function of electron temperature and concentration and consider the effect on the decay rate, for some typical stellar conditions, of the statistical distribution of electrons, the electron-nucleus Coulomb interaction, relativistic and nuclear size corrections, the imperfect overlap between initial and final atomic states, and electron screening in bound decay. We also analyze the experimental information on Be⁷ and Li⁷ to obtain accurate experimental Gamow-Teller matrix elements for both the ground- and excited-state transitions and compare these matrix elements with the predictions of some simple nuclear models. This comparison supports the conclusion of other authors that near the beginning of the 1p nuclear shell L-S coupling is better satisfied than j-j coupling.