Absolute rate coefficients for photorecombination of beryllium-like and boron-like silicon ions

We report measured rate coefficients for electron–ion recombination of Si forming Si and of Si forming Si, respectively. The measurements were performed using the electron–ion merged-beams technique at a heavy-ion storage ring. Electron–ion collision energies ranged from 0 to 50eV for Si and from 0 to 2000eV for Si, thus, extending previous measurements for Si (Orban et al 2010 Astrophys.J. 721 1603) to much higher energies. Experimentally derived rate coefficients for the recombination of Si and Si ions in a plasma are presented along with simple parameterizations. These rate coefficients are useful for the modeling of the charge balance of silicon in photoionized plasmas (Si and Si) and in collisionally ionized plasmas (Si only). In the corresponding temperature ranges, the experimentally derived rate coefficients agree with the latest corresponding theoretical results within the experimental uncertainties.