Stark broadening of singly ionized-silicon

Abstract

Linewidths and shifts of the five prominent visible Si II multiplets are measured in a conventional shock tube. The Stark effect from impacting plasma electrons is the dominant broadening mechanism. Electron densities range widely [(4-15) \ifmmode\times\else\texttimes\fi{} ${10}^{16}$ ${\mathrm{cm}}^{\ensuremath{-}3}$], but temperatures (9500-12 500\ifmmode^\circ\else\textdegree\fi{}K) do not. Optical depth and source inhomogeneity are rarely troublesome. Depending upon interference, blending, and signal-to-noise ratios, broadening-parameter accuracies are between 15-25% and shift uncertainties are 15-100%. Comparison data are examined.