The7Be Electron Capture Rate in the Sun

For solar conditions, we numerically integrate the density matrix equationfor a thermal electron in the field of a Be-7 ion and other plasma ions andsmeared-out electrons. Our results are in agreement with previous calculationsthat are based on a different physical picture, a picture which postulates theexistence of distinct continuum and bound state orbits for electrons. Thedensity matrix calculation of the electron capture rate is independent of thenature of electron states in the solar plasma. To within a 1% accuracy, theeffects of screening can be described at high temperatures by a Salpeter-likefactor which can be derived from the density matrix equation. The totaltheoretical uncertainty in the electron capture rate is about 2%.Comment: LaTex, 19 pages, 2 tables, submitted to Ap