Experimental stark widths of Xe II and trends in the broadening of homologous rare-gas ions

Stark broadening of $6s-6p$ and $5d-6p$ singly ionized xenon lines is measured as a function of electron density $6\le N_e\le 18\times {10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$ in a gas-driven shock tube. Doppler and resonance broadening, and radiative trapping, are negligible at $10.2\le T\le 12.4\times {10}^3$ K and $2\le N_{\mathrm{Xe}}\le 8\times {10}^{17}$ ${\mathrm{cm}}^{-3\mathrm{}}$. Results are compared with theoretical predictions and with trends in the broadening of ions in the homologous structure sequences: Ne II, Ar II, Kr II, Xe II and Mg II, Ca II, Sr II, Ba II.